Re: [pinhole-discussion] WPPD 2003
- Original Message - From: Richard Heather rheat...@slonet.org Actually it seems that there are 1159 submissions! That is right Richard, but only 1082 hang in the gallery, the remainder 77 were rejected for not complying with the submission rules (i.e., only one image per participant) or simply because there was no actual image in the submission, in which case the participant was notified and invited to re-submit the image. Guillermo
Re: [pinhole-discussion] Pinhole tunnels (was Vegan pinhole)
- Original Message - From: Michael Healy mjhe...@kcnet.com I have tried using an old Cronos shutter on my 7x17 but it vignettes something fierce. Its diameter is about 18mm, but it's also about 15mm deep. I think it was designed for a 110 camera on monorail. I have a bigger shutter on the way, so the problem is going away; but is there some formula handy for figuring out how to anticipate the wall's thickness so it falls outside the pinhole's (120 degree?) sweeping view? I barely passed geometry to begin with, and now that half the brain cells have been killed off over the years, there can't be any memory of it left anyway. Any thoughts? There are many things to consider, one is: do you really need 120 degrees of view (DV)? the DV, BTW, depends on the diagonal of the format and the focal length of your camera. Now, assuming you do need 120 DV, the formula to anticipate the wall's thickness would depend on where inside the shutter you mount your pinhole. There are 3 cases: 1- installing the pinhole right midway inside the shutter: In this case the wall thickness has to be smaller than 1.732 times the diameter of the shutter's opening (in case you ask 1.732 = Tan[120/2]). In your example, with a shutter 18mm in diameter, the wall thickness should not be more than 18 / 1.732 , in other words it can not be thicker than 10.39mm 2- installing the pinhole anywhere from flush with the rear of the shutter to just before midway inside the it. In this case, if we call I the distance from the rear of the shutter to where the pinhole is installed and W the diameter of the shutter, the wall thickness has to be less than: [W / (2 * Tan(120/2))] + I 3- installing the pinhole anywhere from flush with the front of the shutter to just before midway inside the it. In this case, if we call F the distance from the front of the shutter to where the pinhole is installed and W the diameter of the shutter, the wall thickness has to be less than: [W / (2 * Tan(120/2))] + F Case 1 is a particular case of both Case 2 and 3. The 3 Cases could probably be combined into 1 single formula, but at this point of the night my brain cells are not functioning quite well, so I better hit the pillow. Mike Healy Tempe (110 degrees in the shade), AZ Guillermo (my tomato plants almost die last nite when temp went around freezing mark) (It will be warmer tonite 42F.life in the great white north :-)
Re: [pinhole-discussion] Vegan pinhole
- Original Message - From: Michael Healy mjhe...@kcnet.com Say, Guillermo. The local supermarkets are packaging four bell peppers together now in special clear plastic bags. You get a green one, a yellow one, a red one, and an orange one. Think you could make a pinhole happen with this? Sure, I'd take the red one, remove the seeds, mount a pinhole and load it with MGIV. The red would act as safelight. I'd then grill the other ones, peel the skin, julien them add some balsamic, olive oil, oregano (you-know-what-I'm-saying). Also, have you seen the microwavable baking potatoes yet? You don't expect a pinholer to use microwave, do you? Actually, I do microwave, but only photo chems, pop-corn and water for tea It's an Idaho special, wrapped in plastic. You just nuke eat. I'm thinking, if you nuked one of these and carefully scooped out the innards (add butter later, oops, that's a cow), you might be able to turn the carcass and the plastic wrap into a (you-know-what-I'm-saying). Pin-tater camera..final answer. I'd be happy to mail you a few these if they haven't made their way north of the border yet. Sure, but send me the butter and the cow also as I am not really a vegan. But a whiskey tube. Come on, how much more vegetarian are you going to get? You got that right. And the answer to that question is not beer cans Answer is not beer cans eh?.can I ask the audience? hold it.what about a wooden beer keg? it'd make a nice big pinhole camera, wouldn't it? Sorry people, the list has been so quiet that this semi OT message could not possible be considered wast of bandwidth...I hope. Guillermo
Re: [pinhole-discussion] wish me luck!
- Original Message - From: Stewart C. Russell scr...@sympatico.ca I've made three cameras (out of whisky bottle tubes), We use to have very regular people by eating lots of oat meal to make Quaker pinhole cameras, cool breathed people after eating lots of Altoid mints, people became cigar smokers to use the nice cigar wooden boxes for pinhole and now we have drunks, were will it end? :-) Myself, I am a vegetarian fan so I am waiting till broccoli comes in nice sealed containers, is there any side efect to broccoli? :-) cut and measured my pinholes (using a modification of Guillermo's flatbed technique), That reminds me of the update I made to this flatbed technique page that I have not uploaded yet. Just did, BTW, it is nothing to write home about, it just mentions that people owning graphic programs with measuring capabilities, like Photoshop Measure Tool can measure the pinhole directly on the screen with that digital tool. http://members.rogers.com/penate/diameter.htm and made three exposures. I'm just about to develop them ... Let us know how they turned out. Welcome to the list. Guillermo
Re: [pinhole-discussion] enlarging paper negatives
- Original Message - From: Shannon Stoney shannonsto...@earthlink.net Hi, just wondered if people ever put paper negatives in the enlarger. If so, are there any problems with it? If the question were: is it doable? my answer is yes and I have done it once, mainly out of curiosity. I loaded a 35mm disposable camera with a piece of MGIV and then enlarged the resulting paper negative to 6x6 size. You can see the result here: http://members.rogers.com/penate/doll6x6.jpg , BTW, the inset negative doesn't have the same proportions of the 6x6 print. I personal don't see a reason to enlarge paper negatives (any size) regularly, I'd rather shoot paper the size of the intended final print and contact print them after. Guillermo
Re: [pinhole-discussion] Finney Pinhole
- Original Message - From: Christian Harkness christianharkn...@hotmail.com Well, no!!!??? You should not be getting a sharp image - isn't that one reason for using pinhole in the first place. If you want that with your 35mm camera, you best use a Nikon lens. Interesting, opinion. Here is mine: You should not be getting a soft image from a glass lens, ins't that one reason for using a glass lens in the first place?. If you want that, you are best using your pinhole camera. For some reason I think it is less easy to accept this statement. In my case, I make images for my consumption alone, sometimes I feel like sharp pinhole images sometime I feel like totally defocused ones, which is the reason I want to know what's the so called optimum pinhole, this way I know what size to avoid when I want them defocused and what size to target for when I want them sharp. Nothing wrong, IMO, with wanting relatively sharp images from pinholes, some times. It's a very cool product. However, all the pictures are soft (not always cool). Not always cool : I agree with that, sometimes is good some degree of sharpness, altho nothing is never really sharp with pinholes. Guillermo
Re: Re[2]: [pinhole-discussion] Zone plates pinhole sieves
- Original Message - From: Colin Linda McKie colinmc...@xtra.co.nz You don't say anything about hardware, but I guess from the quality and square format you're using some kind of 6 x 6. We're trying to decide whether to get a zone plate and pinhole sieve for our P67 with a bodycap mount, or butcher an old TLR (Lubitel etc?) to get a good viewfinder without having to fit a lens for aiming. Comments welcome from anyone with experience in this line. Colin+Linda, I have 2 Lubitels fitted with ZP (one) and Pinhole Sieve (other one), if you mount the ZP or Sieve in th eplace of the rear glass element, you'd get a 65mm focal length, they work very nice for me. I have a third Lubitel that I will turn into a 65mm Pinhole camera to complement my Agfa 6X6 converted to 35mm pinhole. For ZP and Sieve, a shutter is almost a must (it is for me anyway) and you can still use the shutter of the Lubitel. I haven't used a P67. Guillermo
Re: [pinhole-discussion] WPPD
- Original Message - From: Michael Healy mjhe...@kcnet.com WWPD is under the belt! And it has been a great experience. I spent about 5 hours lugging around the 4x5, in the heat, I should say. We had ninety four degree heat today. My film turned to jelly. My brain fried like bacon. Listen, it's been a load of fun! So -- I hate to sound like a whiner, but. What do you say we do next year's in January, when the weather is bit more civilized? Michael, Remember it is a global event, it may be civilized in January in your region but it would be way bellow freezing in some other regions and probably half way to boiling temperature in many parts of the southern hemisphere. End of April represent a compromise, when the northern hemisphere is in spring and the southern one is in autumn. Guillermo (speaking for myself) Who can't plant flowers outside in the flower bed until 3rd week of May w/o risking them to frost!!.
Re: [pinhole-discussion] The panopin
- Original Message - From: CJ Rumpolo rump...@yahoo.com No I fully understand it would be unfair (if not illegal) to use someone elses ideas without consent. I really have no plans on stealing another person's hard work and design. I tend to look at things I like, then try to make them myself. Call it a test of my thinking skills. My current design is from another person's website but have run into a snag of film transport. Today I pretty much considered on giving up the whole project and just stay with the camera I have. CJ, Don't feel bad, do not give up in your project, firstly: you are trying to make a camera for yourself, not to massively produce it, secondly: there aren't too many manual ways you can turn the film cartridges inside a camera, 120 roll like cameras have been manufactured since the end of 19th century (I think) and those patents are now expired. If you take a look to early 20th century rolls film cameras winding mechanism you will find similarities with current 120 cameras mechanisms. I figure if I am using a 4x5 camera and I make a mask to give me two images of 2 x 5 on one sheet of film then I can enlarge the negative to pretty much panoramic scale. That's a good way to make panoramics, you just need a dark slide cut like this: http://www.benderphoto.com/2x5pa.htm The only thing I was thinking about was the curved film plane. I am guessing lenses use their curvature to correct for this and pinholes need the curved film plane to make the image appear as seen. Regular photo lenses don't use their curvature to correct what you think. Curved film plane pinhole cameras help you lower the light fall off. I tried to email Kurt from his site, hoping to purchase a camera, Other plans I had were to purchase an old view camera and convert it to a really expensive pinhole camera. If I remember correctly, Kurt's camera was priced at around $1000 and worth every penny, do the math, you could buy several old view cameras with the price of one of Kurt's camera. So don't think that buying a old view camera and using it as pinhole camera is a bad or expensive idea. Then again I should use Mr. Au's camera more often as well. Its really a nicely made device, though I think its focal length is a bit too wide to my style of photography. Then an old view camera may be good for you, perhaps a press camera or if I you have the money, get a 4x5 Shen-Hao http://www.shen-hao.com it sells for $625 at http://www.badgergraphic.com/search_product2.asp?x=2594 (a steal at that price) and if later you want to do glass lens 4x5 you just get the lens. Guillermo
Re: [pinhole-discussion] Pinhole Lens... ???
- Original Message - From: Guy Glorieux guy.glori...@sympatico.ca Has anybody ever heard of this: a Minolta Pinhole Lens? Seems like a contradiction in terms... But it's there, on eBay! Guy, I think it is nothing but a regular 50mm lens to which a pinhole has been added, probably inside the lens itself and in between the front and rear elements, by leaving a good portion of the lens uncovered you are assured to be able to frame the shot using the viewfinder, then you close the aperture until it covers the round black portion on which the pinhole is made or mounted and make the exposure. This lens will provide enormous DOF at expenses of diffraction. Not a pinhole lens in the sense we use them, but a trick many model builders (trains, ships, etc) utilize to make images of their creations and get a DOF that is close to what they would get if the subject was life size. Guillermo
Re: [pinhole-discussion] Happy Easter!
- Original Message - From: Guy Glorieux guy.glori...@sympatico.ca May this weekend bring happiness and quiet peace to you and those around you. And many beautiful pinole photographs...! And I say amen to happiness and peace for this weekend, as for the beautiful pinhole photos, I wouldn't mind a delay of 1 week for that wish to come true :-) I am going to say it the way I'd say it in Spanish: Happy Holy week, everybody. Guillermo
Re: [pinhole-discussion] Angle of projection
- Original Message - From: p g crd...@lycos.com Is there a simple formula, for the mathematically challenged, to calculate the light's angle of projection relative to the plane of an orifice as diagramed below? For the Lenox's Pinhole Competition, the camera is designed with multiple adaptors to reposition the disc to other locations using 1/2 interior diameter PVC fittings. I want to calculate how far below the 0.585 mm aperture the fitting can extend without protruding into the image's projection. Using this hardware the fittings will need to extend 10-12 mm below the disc. Will this work, or do I need to change the design? P.G: Your pinhole, if it is mounted right at the center of the fitting and if the fitting extend 12mm bellow the pinhole, will project an unobstructed cone of light of about 90 degrees (93.246 to be more exact). Will it work or do you need to change the design? It will as long as your camera is made with a focal length not shorter than half the diagonal of the format you are using. If you need shorter focal length than half the diagonal of the format, just use a fitting with a larger I.D. For math challenged, the best is to make a scale diagram on paper. Forgot the formulas, tell me if you really need them. Guillermo
Re: [pinhole-discussion] Determining correct aperture (wasRE: pinhole photography)
Shelley, First, pinhole photography's technical aspects are not different from those of glass lens photography, and that includes f/stops. So you can get/make pinhole apertures that would give you f/stops that CLOSE DOWN in the same sequence of full stops you are use to with glass lenses, i.e., closing down from f/16 to f/22 to f/32, f/45...,f/128, f/180, etc. that unfortunately would require to make pinholes to the proper sizes that would give you the above aperture numbers. More often than not we end up with f/stops that aren't full stops, like f/160. As you can see, f/160 falls between f/128 and f/180, one could make the math calculations and find that f/160 is just about equal to f/128 +2/3 stops. Since pinhole is not an exact practice and since pinhole exposures tend to be more underexposed than overexposed and since for practical reason is best to use full stops rather than fractional, the wise thing to do is to approximate f/160 to the next smallest full stop, f/180 in this case. Guillermo
Re: [pinhole-discussion] WWPD III
Chris has coded the frames for no scrolling, not a good idea, obviously. There are only 6 images per artist, so if you have 1024x768 resolution, the last thumbnail (1/2 visible in IE6) is the last image of each artist. When using IE, pressing F11 key will allow you to see all of the thumbnails. Another way to see them all is to right click on the artist names, that will give you a scrollable page with the thumbnails, then you drag and drop the thumbnails, one by one, into another browser window, that'll open the full size images. It shouldn't be this difficult, tho. BTW Chris: that's a very ingenious camera you have made, if I were not an I gotta made or modify the pinhole cameras I use kind of guy, I'd have placed an order already. I very much like the images, especially Mia's House, outstanding!!. Guillermo - Original Message - From: George L Smyth glsm...@myway.com To: pinhole-discussion@p at ??? Sent: Monday, April 07, 2003 5:44 PM Subject: RE: [pinhole-discussion] WWPD III For some reason I do not get a scroll bar on the right, so I am not able to get to all of the images in the left frame. Cheers - george
Re: [pinhole-discussion] disposable camera pinholes
That dremel drill bit is defenitely a good one to use, it is bit #125 and you can make holes of up to 1/4 with it. BTW, the secret to convert a disposable camera to a pinhole one is: Get 2 already used disposable cameras, dissasemble one, if you have to damage it, so be it, that's the reason for having 2 of them, once open, study how the different parts latch with each other, this will allow you to disassembly the other camera safely. Then study the film advancing mechanism, this will teach you how to reload the camera and if the new film cassette has to suffer any modification, remove the lens, install a pinhole, reload the camera with the film, which has to be done under darkroom conditions. Guillermo - Original Message - From: D. Hill zopp...@yahoo.com You do not need a special drill bit - just one that isn't too big, nor too small - anything 1/8 inch and smaller is a good starting point. A useful bit is made for a Dremel Tool and is shaped like a cone. If you drill from the front, it makes a nice beveled edge. --- sherry rea slrshe...@yahoo.com wrote: will someone please share the secret of making a pinhole cmaera from disposable cameras and also is there a special drill bit that should be used for the body cap pinhole?
Re: [pinhole-discussion] bodycaps.
- Original Message - From: bendur...@aol.com I was asking on friday how to make a pinhole body cap. I was wondering, do all the mirrors and thing in my SLR make it not work for pinhole. Ben, As long as a cameras has a setting that allows the shutter function to work, that is: lift the mirror and open up the shutter when the shutter realease is pressed, that camera is fit fit for pinhole practice. I assume some cameras' shutter function may not work if a real lens is not installed, cameras with electronic links between the lens a the body may require to be set for manual exposure and/or manual focusing. Guillermo
Re: [pinhole-discussion] 6x22 pinhole camera coverage?!
- Original Message - From: Tom Miller tomwmil...@attbi.com To: pinhole-discussion@p at ??? I've read a rule of thumb that at 30 degrees the fall of is one stop and that at 45 degrees it is two stops. It seems like there is a possibly handy formula in there. Tom, Forgot answering this other question. That rule of thumb is good, but to be precise, 1 stop is at 32.76 degrees. A formula to find the angle at which a specific fall off is found would be: If S = stops of fall off Angle = ArcCosine [(1 / 2^S)^0.25] or for better clarity: http://members.rogers.com/gpenate/angle.gif for 1 stops it would be: Angle = ArcCosine [(1 / 2^1)^0.25] Angle = ArcCosine [(1 / 2)^0.25] Angle = ArcCosine [0.5^0.25] Angle = ArcCosine [0.840896] Angle = 32.76 degrees for 2 stops it would be: Angle = ArcCosine [(1 / 2^2)^0.25] Angle = ArcCosine [(1 / 4)^0.25] Angle = ArcCosine [0.25^0.25] Angle = ArcCosine [0.70710678] Angle = 45 degrees Guillermo
Re: [pinhole-discussion] 6x22 pinhole camera coverage?!
- Original Message - From: Tom Miller tomwmil...@attbi.com To: pinhole-discussion@p at ??? This put two questions in head. First, would a concave film plane reduce the fall off ratio? Optimally, the film plane could be curved in a way that makes the entire film plane equally distant from the pinhole. I looked at the 6x22 camera's photo on the silver-whatever web site and it looked like it could possibly have a curved film plane, although I couldn't tell if would be hemisperical like the Mottweiler Pinoramic. Disclaimer, none of the these is needed to be known to practice extreme wide angle pinholing, but if somebody ask this questions, I am happy to oblige. Tom, The camera in question looks very thin, so I am pretty sure it is a flat film plane camera. Yes, a concave film plane would reduce the fall off ratio. Using a film plane conforming to a half circle and positioning the pinhole at the center of the circle would reduce the fall off by a very substantial amount. In math terms, it is reduced from being cosine^4, to just cosine of the off axis angle. There is a catch, tho, in the case of this camera (6x22), the focal length has to be increased to allow the width of the film to fits in the semi-circle. Second, what is the formula that you used to calculate the fall off? I'm curious because I've been doing a fair bit of extreme wide-angle stuff lately and it doesn't seem like the light falls off as much as one would think. I think that we expect pinhole images to have severe fall off, therefore the actual fall off we get doesn't look to be that severe (am I making any sense?), it is almost magical and even seemingly defying physic laws! but I am pretty sure is just subjective perception. It is a flat film plane camera with a 1:3.7 ratio. I've read a rule of thumb that at 30 degrees the fall of is one stop and that at 45 degrees it is two stops. It seems like there is a possibly handy formula in there. There is a law in optics called Cosine^4 law, all lenses, including glass lenses are subjected to it. It says that the intensity of light at a off axis point will be reduced by a factor equal to cosine to the power of four of the off axis angle. In your camera with ratio 1:3.7 (I'll assume this ratio is focal length : width of format), which BTW has very similar ratio than the one we've been discussing 60mm/22cm, the sides of the film are 61.6 degrees off axis, hence, as per Cosine^4 law, the intensity of light at the sides will be just: Cosine(61.6) x Cosine(61.6) x Cosine(61.6) x Cosine(61.6) = 0.051174 In other words, if at the center we have an intensity of 100 units (whatever units), at the sides, it'll be just 5.1174 units. To find how many stops that correspond to, we just multiply 0.05117 by 2 as many times as needed to reach 1 , the number of times you multiply by 2 is the number of stops of fall off. A faster and precise way is using this formula: Stops of fall off = 3.322 x Log ( 1 / 0.051174 ) = 4.29 stops If W = width of camera in mm and F = focal length of the camera in mm, a single formula to find the fall off at the sides of the film would be: http://members.rogers.com/gpenate/stopsW.gif If instead we want to find the fall off at the corners of the film, when H = height of film, the formula becomes: http://members.rogers.com/gpenate/stopsWH.gif Correction welcomed. Guillermo
Re: [pinhole-discussion] 6x22 pinhole camera coverage?!
My inquiry is regarding how an image would look from such a long neg.? The stated aperture size is f/360. Would the edges suffer from extreme distortion? I'm surprised that the coverage would even fill that length of 22cm!? The aperture is irrelevant, the only thing that matters is the ratio width of format to focal length (corner-corner distance to focal length if one wants to be exact). The ratio of that camera is 3.6 which in theory will have a 4.25 stops fall off at the sides with respect to the center, this kind of fall off is horrendous for glass photography, but for pinhole images, in practice, it doesn't look as big as one may think, IMO. As an example, this image http://members.rogers.com/gpenate/greek.jpg is a portion of a larger image made with a camera with ratio 3 width/focal length, that should give a fall off of 3.4 stops at the top and bottom of the image with respect to the center, and if you ask me, it doesn't look that big of a fall off. They share no images produced with said camera so I have doubts, with my limited understanding of pinhole imagery, to how good the detail would be at the extremes? Again, their camera has a 3.6 ratio, my example image has a 3 ratio, that tells me that if the conditions are favorable: clean pinhole, thin material, good lighting of the extremes of the scene, etc., the detail should be acceptableand if it not, I really like the heavy fall off to the edges effect, too. Having said all that, I wouldn't buy or use a camera from that company, reasons are obvious. Guillermo
Re: [pinhole-discussion] Willarney's BB Idea
- Original Message - From: michael_georg...@trendmicro.com To: pinhole-discussion@p at ??? Sent: Thursday, March 13, 2003 6:12 PM Subject: [pinhole-discussion] Willarney's BB Idea Philip Willarney, I salute your brilliantly nutty idea! (And am not surprised Ms. Merrill, our associate in wierdness, came out to comment!). Now, given that an airgun bb has a diameter of .175, we'll need Guillermo to tell us how far apart the inner sides of the box need to be. Without taking my trusty slide ruler out to make the calculation, I can tell you it would need to be like the mother of all pinhole cameras (or not). Guillermo
Re: [pinhole-discussion] freestyle cold-stored color film $ blowout
- Original Message - From: George glsm...@myway.com Did they include a URL? I didn't see anything on their site (I think I was looking at their site). http://www.freestylephoto.biz/clearance.php?wcat=99 Guillermo
Re: [pinhole-discussion] New find for paper negatives...
- Original Message - From: Michael Healy mjhe...@kcnet.com I imagine half a case of Home Depot toilet paper. Ow yes... Don't get Linagraph Direct paper... (Cat 198 6520) ... it doesn't appear to be sensitive to White light at all...man do I have a bunch too... it comes in 12x400' rolls. No comments..needed ;-)
Re: [pinhole-discussion] camera conversion question
Murray, I hope I understood your description (sometimes my ESL comprehension fails me miserably). You are considering (first) the 4 side of the bellows frame opening: Since the bellows do not end at the center of the lens (or pinhole for than matter) but beside the shutter, the angle between them and a perpendicular to either side of the 4 opening is irrelevant, the bellows will not vignette your image unless they sag beyond a line from the end sides of the 4 opening and the pinhole. If the aim is to get a 4x5 image by building an extension box, you should analyze the 3 size first, as the ratio 4 intended image size to 3 opening is greater than 5 image side to 4 opening. If you lower a perpendicular from the pinhole to the film plane, you'll have a triangle (let's call it A) with corners at: pinhole - middle of the 3 opening - end side of the 3 opening, you also have another triangle (let's call it B) with corners at: pinhole - middle of the 4 image size - end side of the 4 image size, since this 2 triangles have equal angles, we can write that: Base of A divided by Base of B = height of A divided by height of B Base of A is half the 3 opening = 1.5 = 38.1mm Base of B is half the image size width of 4 = 2 = 50.8mm height of A = bellows extension = 130mm height of B = height of A + extension box deepness EBD = 130 + EBD So you have: Base of A / Base of B = height of A / height of B 38.1 / 50.8 = 130 / (130 + EBD) EBD = (130 * 50.8 / 38.1) - 130 EBD = 43.33mm An extension box of 43.33mm will give you an image width of just 4, since my skills and tools to make cameras or modifications to existing ones aren't that great, I'd make it at least 46mm deep instead. A similar analysis can be made for the other side and the result would be 1.28 (close to your finding of 1.25), but since it this result is smaller, you have to use the larger one of 43.33mm, which is equal to just above 1.7 All the above could have been explained fast and nice with a simple drawing, but this is just an ascii posts only list. Guillermo - Original Message - From: Uptown Gallery mur...@uptowngallery.org Gutted some Polaroid rollfilm cameras with 130 mm lens/bellows. Extends a little farther than that due to 3.5 feet to infinity focus adjustment. Pulled lens, kept shutter for experimentation on one. Rear opening of bellows frame is a hair larger that 4 x 3. I took some measurements along 4 axis and calculated a 22 degree angle for the bellows. From this I figured I need a 1.25 entension box to get a 5 image. I didn't calculate or measure the short side yet...might be different due to aspect ratio of 4:3 differing from 5:4. Gonna try ground acrylic instead of glass. Question is, with a pinhole I should have adequate coverage, but do you think my anticipation of angle will prevent 'vignetting' by the bellows or rear of the camera (existing opening?) Thanks Murray ___ Post to the list as PLAIN TEXT only - no HTML Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] Guillermo's 5 lp/mm optimum design
- Original Message -
From: HypoBob hypo...@pacbell.net
Guillermo,
In a posting on 13 December you stated that an 8x10 pinhole image rivaling
the resolution of a lens image (i.e., 5 lp/mm) could be obtained with a
focal length of 120 mm or less and the optimum pinhole.
Since one could place any size negative material in such an arrangement,
aren't you in effect saying that a 120 mm focal length is the maximum for
obtaining 5 lp/mm resolution?
Yes, but those 5 lp/mm are on the film which is more often than not and
intermediate step to the final result, the latter being, more often that
not, a positive print. So although the resolution you may have on your
35mm format made with the optimum size pinhole 50mm body cap is better than
5 lp/mm when you enlarge it to 8x10 you will get a print with just about 1/8
the resolution on film. If you didn't have to enlarge and view the print at
the normal distance of comfortable vision, then, the 5 lp/mm are enough.
Now, if you make a 16x20 pinhole camera and view that print at a distance
equal to twice the normal distance of comfortable vision, you will then
only need 2.5 lp/mm on the print, in which case 480mm focal length would be
the maximum.
Is there also a minimum focal length for this resolution?
Not mathematically, but practically there is. For a given format, there is
a minimum limit of the focal length that would acceptably cover the film
format, as well as there are practical limits forced by how small a camera
we can make, a manufacturer of laser drilled pinholes once sent me a 0.001
pinhole good for an optimal focal length of under 0.5mm!! I couldn't
possible make a camera with such focal length.
Do you have some equations you can share with us that give the
relationship between resolution, focal distance, and pinhole size? I'm
guessing
that this all may be based on the usual equations with a properly chosen
value for the circle of confusion.
Resolution = 1 / (1.22 * wavelength * fstop)
if you use wavelength = 0.00055mm, it becomes:
Resolution = 1490 / fstop
Assuming you know the resolution and want to know what fstop would give you
that resolution:
fstop = 1490 / resolution
but, fstop is also equal to:
fstop = Focal length / pinhole diameter
and:
pinhole diameter = 0.03679 * SQRT(Focal length) {units in mm}
therefore:
fstop = Focal length / (0.03679 * SQRT(Focal length)
or also written as:
fstop = 27.1813 * SQRT(Focal length)
therefore:
Focal length = ( fstop / 27.1813 )^2
How did I get 120mm as the maximum focal length I talked in my post?:
I started with the need of 5 lp/mm, therefore:
fstop = 1490 / resolution
fstop = 1490 / 5
fstop = 298
Focal length = ( fstop / 27.1813 )^2
Focal length = ( 298 / 27.1813 )^2
Focal length = 120mm (aprox)
In any event, it seems that the conditions will hold only 'near' the
center of the image because the corners and edges are beyond the optimum
focal
distance.
That is true, but you could have a semicircular film plane with the pinhole
in the center of the semicircle, in which case the distance pinhole film
would be constant (in one axis, at least). Make the film plane half an
sphere and you will get same distance everywhere on the film plane :-)
Also, I'm thinking that you may be assuming a certain viewing distance for
the observer since smaller images tend to be held closer to
the eye than do larger ones. That is, the 8x10 size may be necessary to
get the viewer to hold the 5 lp/mm print about 20 inches from his eyes
rather than the 12 inches at which he may hold a smaller 5 lp/mm print.
That is correct.
Thanks for getting me off onto this tangent. I always enjoy your posts,
Thanks, I enjoy posting them, it keeps my brain from getting rustier.
BTW, corrections to the above are welcome.
Guillermo
Re: [pinhole-discussion] #80 drill bit
- Original Message - From: Traci Bunkers bonk...@bonkersfiber.com I also have a dremel with a flexshaft. I wondered about it, but thought it would pose the same issues as the drill. I thought about layering a bunch of pieces from aluminum cans and drilling through them all at once. Has anyone tried this? I guess there's only one way to find out if it will work! Unless you have a way to clamp/compress securely all the layers, the drill bit would likely brake. What you need is a drill press like this one: http://www.dremel.com/html/products/toolsacc_fr.html , I got one and although I don't use it to make my pinholes, I have used it and works beautifully for that purpose. Guillermo
Re: [pinhole-discussion] The next Epson scanner after the 2450?
- Original Message - From: Richard Heather rheat...@slonet.org To: pinhole-discussion@p at ??? Sent: Saturday, January 04, 2003 1:34 AM Subject: Re: [pinhole-discussion] The next Epson scanner after the 2450? I have a 2450. The resolution at 2800 gets grain with most films. Unless you shoot TechPan or Kodachrome 25 I doubt more rez will improve the image. Somehow TriX 5x7 (inches!) seems grainier than 35mm. Richard Heather That actually is good, the grainier the film looks the better the scan is (if that grain is the actual grain of the negative). Higher resolutions are not used to improve the image but to capture the image the way it actually is. BTW, you also see the film grainier if you see it with a enlarger focuser, it is the same thing. Remember that when you scan at a resolution of 2450 DPI, your monitor, assuming the resolution is 1024x768, can only display a rectangle 0.3 by 0.4 inches of the total area of the film, it is the equivalent of enlarging your 5x7 to 80x114 inches size. Guillermo
Re: [pinhole-discussion] Season's greetings to all!
- Original Message - From: Mike Vande Bunt mike.vandeb...@mixcom.com Well said! (You don't have to pay royalties to Mel Torme for the use of that line, do you?) ;-) What do you mean, Mike? Last nite I was roasting some chestnuts on an open fire, when suddenly came to me the fact that people try to say Merry Christmas in so many different ways these days, some trying to be inclusive, some trying not to offend others, some trying to offend others and some trying to be just politically correct. In my city's City Hall, what always was known as a Christmas tree, now it is called Holiday tree!. Anyway, as I said, I was roasting these chestnuts on an open fire, when the line just came to me!! in part for the above in part 'cause I thought I could used the shell of a chestnut to make a pinhole camera. :-) Guillermo
Re: [pinhole-discussion] Season's greetings to all!
Though its been said many times, many ways Merry Christmas to (all of) you! Guillermo
Re: [pinhole-discussion] Yet another lensless technique !!
- Original Message - From: George L Smyth glsm...@yahoo.com I like that very much. Now it's a matter of either figuring out the specifics of how to make one and/or waiting for someone to offer them commercially. George, Since I am offering zone plates already, I will add Photon Sieves and Pinhole Sieves to the offering, wait for an announcement on this. Guillermo
Re: [pinhole-discussion] What is Diffraction?
- Original Message - From: Guillermo pen...@rogers.com As we all know pinhole is not about sharpness, nor I am suggesting we strive for it. Having said that, it is actually possible to make poinhole images that under certain conditions could be undistinguishable from glass lens images. A good example is an image in the Renner's pinhole book. Under the assumption that we humans can discern more than 5 line pairs per millimeter, The last statement should have read: Under the assumption that we humans CAN NOT discern more than 5 line pairs per millimeter with the unaided eye Guillermo
Re: [pinhole-discussion] polaroid pinhole.
- Original Message - From: bendur...@aol.com Dear All I was wondering if could help me. I want to do polaroid transfers, and want to know if anyone knows a cheap an effective way to make a polaroid pinhole camera that can do this. Ben, The easiest and cheapest would be to get yourself either a Polaroid holder or camera that takes the film you want to use and then you build a wooden box around the holder and or modify the camera to make it a pinhole camera. There are always holders and cameras being auctioned at eBay that can serve the purposes mentioned, these are some currently being auctioned: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=1944584085 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=1944512695 The main thing is to make sure the holder or camera actually takes the film you intend to use, as there are older Polaroid holder/cameras that may seem to take modern film but they will not, so do your homework before bidding. I bought an oscilloscope camera at eBay, from that purchase I have a shutter like this http://tonopahpictures.0catch.com/G-Claron/Ilex75_4.jpg that I could use for pinhole , a close up lens I use as paper weight and a holder exactly like this one: http://tonopahpictures.0catch.com/021502/pinhole0.jpg http://tonopahpictures.0catch.com/021502/pinhole2.jpg that I also converted to pinhole camera. Disclaimer: those auctions above are just to give you an idea, I do not know the persons auctioning that stuff nor I have any interest in them selling it. Guillermo
Re: [pinhole-discussion] I am so not done wondering!!!!
Ok, I get it, digital stuff is just another way of doing it,as for the real question: Is it art? Just kidding people, just kidding :-)
Re: [pinhole-discussion] wondering
- Original Message - From: Dan Gerber dger...@adobe.com Seriously, I spent almost every waking hour of my 4 years of college in the darkroom, and yet now, when I own a home with a lovely space for a darkroom, and all of the equipment I need(x2!) I don't have a darkroom! Why? Because I don't need one for the type of work I do, and my highly experimental nature has led me to digital processes(it also doesn't help that I work for Adobe!) They offered me a job, but when I read the contract, the line where it says: Thou shall not do it in the dark, I declined to sign. :-)
Re: [pinhole-discussion] New Camera from Joaquin Casado and prompt box
- Original Message - From: George L Smyth glsm...@yahoo.com Hmmm, okay. Very poor website design. I would like to see more pictures, get more details, maybe even find out how much it costs. I have no desire to send him an email. Anyway, I do my email through Yahoo, so this doesn't do me a whole lot of good. Too bad that something that should be so simple becomes impossible. I wonder if the camera is similarly designed. Common George, give Joaquin a break. The 1000's words the pictures in his site say speak very loud of his design and craftmanship. I said in my post that this was a PRE-ANNOUCEMENT. Joaquin sent me and a couple of other persons an email for us to PRE-VIEW his new creation, the site IS NOT meant as THE site from which he'll sell this camera, nor it is intended to ANNOUNCE the camera to the world, it says in the home page that there will be a web site coming soon. I'll stop short of saying I made a mistake with my posting of Joaquin pre-announcement to the list, Joaquin indicated to me, he was surpriced to find this morning so many emails from people interested, so no question some people were impressed with the beauty of the cameras and wanted to know more. Guillermo
Re: [pinhole-discussion] New Camera from Joaquin Casado
- Original Message - From: George L Smyth glsm...@yahoo.com It does look pretty cool, though I wonder about the cost. I clicked the link for more information, but got a Prompt box that then got rather confused. Oh well. Usability is the most important thing on Web page. My mistake, I should have pointed to the HOME page instead, in it Joaquin mentions: This is just an exerpt from our new Website,which will be published soon. About the cost, I wonder about that myself, I am pretty sure it'd be an as handsome sum as the cameras themselves. Guillermo
[pinhole-discussion] New Camera from Joaquin Casado
Joaquin Casado, maker of the handsome 4x5 Hal Camera has know pre-announced the beautiful Curva120, as the name implies, it is a curved film plane taking 120 film. Incredible design. Take a look: http://usuarios.lycos.es/jsendec/curva_english.htm Guillermo
Re: [pinhole-discussion] uploaded photo with thing in corner
- Original Message - From: Jeff Dilcher r...@hiddenworld.net Looks like a light leak. I think Holga owners considers that a feature and not a problem! There is a reason these cameras were (originally) inexpensive... Some Holga aficionados would kill for a Holga with that problem.
Re: [pinhole-discussion] [pinhole-dicussion] reciprocal failure
- Original Message - From: karol dzikamal...@interia.pl i've got an Zero Image pinhole camera and i've got a question concerning sth called 'reciprocal failure'. In a instruction added to a camera it's written that it means that i need to multiply the speed by 2 when it's 1-2seconds, by 4 when it's 2-4...by 12 when it's more then 10 or sth like this. anyway it's written in a very simplified way so i'd like to know some details. the aperture in this camera is 138. Karl, Exposure is given by a pair of parameter, they are: Time and Aperture, there is a reciprocal relationship between them. That means that if you increase one of the values by a factor X and decrease the other by the same factor X, the exposure will be the same. An example: 20 times 40 is equal to 800, but if you halve 20 and double 40, their product will also give you the same result 10 times 80 equal 800. Another example: f/60 @ 1/200 secs = f/90 @ 1/100 secs. Unfortunately, when your exposure time gets (usually) bellow 1 sec or higher than (usually) 1/1000 sec, that reciprocity between Time and Aperture fails, hence Reciprocity Failure. The effect is that you will need to expose for longer than what the reciprocal relationship is telling you. Each film has its own characteristics, therefore, each film FAILS in a different way. Guillermo
Re: [pinhole-discussion] RE: pinhole size
- Original Message - From: Paul Prober pro...@silcom.com The problem experimenting with different pinhole sizes is that unless we are making exposures of resolution targets http://www.???/resources/articles/Young/images/fig5.jpg the results will be always subjective to each viewer, scene, image contrast, whether subject is at close or far from the camera, angle of view, etc, and/or a combination of the above. I have not experimented to find the optimum pinhole size. Chris Patton has, and his conclusion was that the Prober-Wellman Formula is a practical values to use for f/stop to pinhole size for reasonable Circles of Confusion. See http://www.stanford.edu/~cpatton/phcalc3.htm which uses the Prober-Wellman Formula. Patton actually uses a different formula or maybe I should say different constant as all formulas since Lord Rayleigh (1890's) are basically the same. Patton actually has found that bigger pinholes than what most of the rest of us consider optimum, gives him sharper images. OTOH, you have Larry Bullis going the oposite way, that is, he finds that smaller pinholes give him sharper results. Myself, my eyes, rather, are more inclined to align with Larry than with Patton. or http://www.huecandela.com/hue-x/pin-pdf/Prober-%20Wellman.pdf for the white paper study. Also the formula can correct for pinhole to subject distances, for Close-up and Micro pinhole pictures. The Prober-Wellman Formula is exactly what science has been telling us the optimal pinhole formula should be D= SQRT (2.44 * Lambda * F) , the SQRT(1 / M+1 ) factor is a sort of bellows factor as I explained it in a post back in Oct last year: http://www.pairlist.net/mailman/private/pinhole-discussion/2001-October/0042 23.html Guillermo
Re: [pinhole-discussion] Question on image circle and medium format pinhole camera design
- Original Message - From: Philip willarney pwillar...@yahoo.com If the edge is a slow fade from picture to dim picture to black, then it's falloff. Pinholes as such don't have an image coverage circle -- That is correct, the image circle is determined by how many stops at the edges we are willing to tolerate. Those 3X or 3.5X the focal length coverage mentioned everwhere, have no meaning whatsoever, IMO. Guillermo
Re: [pinhole-discussion] Question on image circle and medium format pinhole camera design
- Original Message - From: Fox, Robert r...@aarp.org I'm thrilled with the results! The proofs are properly exposed (surprise given I was using a flap for the shutter and counting the seconds) on Ilford XP2 film (iso 400). I used f64 as the base exposure reading, then multiplied by 6.3, which worked great. Bear in mind that multiplying the f/64 by 6.3 or 6.48 (if you want to be more exact) will give you a reciprocity uncorrected value for the f/stop of your camera. If by any chance you noticed that the longer the exposures the thinner the negatives, that may indicate is time to correct for reciprocity at those levels of long exposures. I'd suggest you take some notes when shooting. Proof print may or may not show up the underexposure, some may even benefit from it!! Question: my images are all circular, cutting off the corners cleanly of the square print. Is this because the image circle is too small for the film? I'm wondering if the circular edge of the front plate is being picked up on film, since the edge sticks up about 1/4 inch. Any time the corners are cut cleanly as you mention, it is probably mechanical vignetting, the front plate is obviously in the way. You could check for mechanical vignetting by opening the rear and aiming the camera to a bright light while having your eye, the corner of the opening (6x6) and the pinhole line up, if you can't see light coming in thru the pinhole, then you have vignetting. Guillermo
Re: [pinhole-discussion] Does Pinhole-Discussion have an archive?
- Original Message - From: Andrew Amundsen a...@tcinternet.net ...how do we access the archives? Could someone post a link? Andrew: You will see a link to the DISCUSSION page, at the foot of each posting, go there and 3/4 down the page there is a link to archives. There are 2 categories of archived messages: those posted previous to 08/22/2000 and those posted after. The former are easier to search than the latter, unfortunately. Guillermo
Re: [pinhole-discussion] SX-70
- Original Message - From: MARK POWER mpo...@coventry.ac.uk Folks, I've tried to dissect a SX-70 for some pin hole fun, but to no avail i.e., I'm frightened of breaking it all together. Any hints? Mark, The Hacker's Guide to SX-70 has the answer for you: http://www.chemie.unibas.ch/~holder/SX70.html Guillermo
Re: [pinhole-discussion] pinhole size
Michael, Pinholes are afocal, meaning: they don't have focal length, per se. You can use them to whatever distance pinhole-film you wish, knowing that if you don't use them to their optimum distance, results will be less-sharp, which depending on the photographer intentions could be good or bad for your resulting image. Knowing that a pinhole can be used at any distance, again, they are afocal, the fall-off is not caused by its size, but by 3 different factors: first: light on the film plane decreases as the distance pinhole-film increases, distance at the center is shorter than distance at the edges of the film, therefore you'll have fall-off as you go off film center. secondly: seen from the center of the film the pinhole looks round (assuming you made it round), but seen from the edges, it would look oval, that translate into less area for light to go thru, that too causes fall-off. Lastly: light falling at the edges, falls at an angle on the film, therefore covers a bigger area of the film, that too, causes fall off. Geekly speaking :) the fall off at the edges will be a factor of the function COSINE to the 4th power of half the total angle of view of your camera, in your case that translate to just over 3 stops. BTW, glass lenses are not exempt of this COSINE^4 condition, that is why for wide angle lenses manufacturers also make special filters to go with them and that correct the fall off at the edges by causing fall off at the center (forgot their name, center filters I think). If you were to use a pinhole optimum for 73mm, your fall off will be the same, the fall off is only a function of the angle of view, in other words, the wider the angle of your camera, the more fall off. Your camera has 109 degrees angle of view, the format diagonal is just 2.8 times the distance pinhole-film, BTW. Optimum does not mean longest, it means if you want the sharpest images possible use this distance, longer or shorter that optimum and the resolution suffers. The only way to get less fall-off is to make the film or paper to conform to a cylindrical shaped film plane and position the pinhole at the center of the circle describing the half cylinder, there are some examples here: http://www.cyberbeach.net/~dbardell/pinhole.html The reason why such cameras have less fall off is that the distance pinhole-film is the same from center to edge of film and also the light always falls perpendicular to the film so it doesn't have to cover more area (as explained above). Something else that contributes to a fall-off is the thickness of the material the pinhole is made of and whether it has burrs around its edges. Guillermo - Original Message - From: Michael Healy mjhe...@kcnet.com I bought the 12-lens set from Pinhole Resourses, and I've been using the .0102/.259mm pinhole on my 4x5. This one's claimed optimal focal length is supposed to be 48mm. I am using it with a recessed lensboard to a length of about 50mm. That's the closest I can get even w/ a bag bellows. The results are fantastic. I love the focal length. Unfortunately, its fall-off is quite noticable. No vignetting, but the fall-off is about 1.5-2 stops from center to edge. So I think I have to try the next one of the bunch, the one whose optimal focal length is reported to be 73mm. That seems like quite a jump, though. Before I try this at a shorter bellows length than 73mm, has anybody done this? Will I have problems just shooting this at, say, my 50mm (w/ bellows compensation)? Does their optimal mean longest? That's what the 48mm seems to mean, that if you go even to 50mm, you'll have fall-off. Anybody w/ experience of this? If this works, should I consider ordering a 50-55mm pinhole to fit my 4x5? I really like the weird, extreme result from the short one -- it's just that the light fall-off makes cyanotypes very difficult to print. I'm anticipating that albumen won't work much better. Thoughts? Mike Healy
Re: [pinhole-discussion] holga source in Chicago?
- Original Message - From: D. Hill zopp...@yahoo.com Calumet stocks them, do they have a storefront? Yes they do, as per their web site: Manager: Greg Hamlin Address: N Cherry St. Chicago, IL 60622 Phone: 312-440-4920 Fax: 312-664-1736 Hours: Monday-Friday 8:30 a.m.-5:30 p.m. Guillermo
Re: [pinhole-discussion] Polaroid Reciprocity
- Original Message - From: Jason Russell jruss...@wishtv.com Will the equation change with different types of film? The equation is just a math model of the reciprocity correction curve, the latter is just a graphic representation of the discrete values, either given by manufactures (like the ones given by Polaroid for the film in question - Polapan type 72) or obtained by us thru experimentation. Since each film has its own reciprocity characteristics, each film would have its own equation. Or do I just plug the indicated time into the equation to get a starting point? If it does change, which numbers will be different and how do I figure them out All the coefficients change. You can find them by doing a Regression analysis of the known reciprocity correction values, I use the Least Square polynomial method, here is a hint on how to do that: http://www.efunda.com/math/leastsquares/lstsqrmdcurve.cfm , for those of us confused by the above, using a program like WinCurveFit http://www.krs.com.au/wcf.html is a good thing, that is what I used to give you the answer BTW. Guillermo
Re: [pinhole-discussion] re:pinhole nude
- Original Message - From: Paul Prober pro...@silcom.com Note! By using flash there is no recopicity failure. The effect is the same as opening the shutter for 1/1,000 of a second each time the flash is fired. Sure, there is a reciprocity like effect, its name is Intermittency Effect. Guillermo
Re: [pinhole-discussion] zone plate
Stanford is incorrectly spelled, it should be STANFORD not STANDFORD. Guillermo - Original Message - From: John Fisher photobu...@hotmail.com Would you check the URL? I have tried to open the site.But haven't had any luck. thank you From: Paul Prober pro...@silcom.com Reply-To: pinhole-discussion@p at ??? Chris Patton at Pinhole and beyond has a zone plate area. The site address is www.standford.edu/~cpatton/zp.html There is many zone plate lens, plus formulas for focusing the lens to subject. Paul Prober
Re: [pinhole-discussion] Zone plates for a body cap
- Original Message - From: Guillermo pen...@rogers.com I gather that by aperture of the zone plate you mean the size of each of the rings. Mr.Pinhole formula is what the scientific community uses for their high-tech uses of zone plates and my non-scientific tests (focusing aerial images produced by zoneplates) have confirmed that. Other use slightly different formulas. I was reading my own post and it seems not to be too clear. What I meant was that when I mount zone plates on my 4x5 view camera and focus on the aerial image until it is a sharp as they would be, the distance zone plate to film plane matches very closely with what the formula Radius = SQRT(wave length x focal length x ring#) would predict. Now, the formula can also be written as Diameter = 2 x SQRT(wave length x focal length x ring#). Some people use formulas slightly diferent, what they change is that number 2, Patton for instance, uses 1.86 http://www.stanford.edu/~cpatton/zoneplatemath.htm Guillermo
Re: [pinhole-discussion] Zone plates for a body cap
- Original Message - From: Beaker mbea...@mac.com Guillermo- how do you figure out the aperture of a zone plate? Mr. Pinhole mentions this formula: radius = sqrt(wavelength * focallength * ring). I was guessing that this would give a good number to start with. Is this a good guess? I gather that by aperture of the zone plate you mean the size of each of the rings. Mr.Pinhole formula is what the scientific community uses for their high-tech uses of zone plates and my non-scientific tests (focusing aerial images produced by zoneplates) have confirmed that. Other use slightly different formulas. One last thing- I've never worked with zone plates before, or even have litho negatives made, so we will learn together what works, and what doesn't! Just one more suggestion, try making zone plates whose number of clear rings give you f/stops that are equal or slightly smaller (numerically) than a full stop, this will facilitate exposure calculations. Guillermo
Re: [pinhole-discussion] using filters
- Original Message - From: Jeremy Jeffs jeremy.je...@virgin.net I've been shooting B+W landscapes on a pinhole camera. To bring out clouds I've been using a yellow filter behind the pinhole - in front would mean than every speck of dirt is in focus. My problem is that specks of dirt cast a blur/shadow on the negs. I've tried vigilant cleaning but can't seem to eradicate them. Any suggestions on keeping contrast in the sky without a filter? Or alternatively how to use a filter without rendering every speck of dirt? Don't mount the filter on the camera, rather hold it in front of the pinhole and keep moving it for the duration of the exposure. The larger the filter the easier this is done. Guillermo
Re: [pinhole-discussion] Zone plates for a body cap
- Original Message - From: Beaker mbea...@mac.com I'm thinking of getting a sheet of Zone Plates made for a Pentax K mount body cap (optimized for 43 mm). Would anyone be interested in buying any? The reason I ask, the negative will cost something like $50 to $75, (the shop has a $50 minimum.) and I would like to spread the cost out a little. For a little more to cover the cost of a body cap, I could send out the finished article. The negative isn't made yet- I'm just trying to gauge the interest, so the price is still to be determined. A sheet made by an image setter can fit lots of ZPs, you don't have to have the whole sheet full of 43mm ZPs, I would suggest you make some other focal lengths as well. 65mm for instance is perfect for attaching it to the back of the shutter of a Lubitel. Another possibility, which is not mutually exclusive with the one previously mentioned, is to make similar focal lengths ZPs but with different number of rings, which will give you different f/stops, I.E., a 43mm ZP with 9 total rings is f/64 (aprox) but a 19 rings one is f/45 and would probably have more of that ghostly effect. I make my own ZPs using lith film, otherwise I'd be joining you, nevertheless I recognize this as a good chance for those that have not experimented zoneplate photography to try it with very minimum investment and help you share the cost in the process, a win/win scenario if you ask me. Good luck. Guillermo
Re: [pinhole-discussion] LARGE FORMAT f STOP QUESTIONS
- Original Message - From: earthecho Hello, Frazer Bryant here - New member from England. Hello Frazer and welcome to the list. The sheet Film size is 8 and a 1/2 inch X 6 and a 1/2 inch. (I will be using paper negs.) I have one of those, only mine is 6 1/2 X 8 1/2 !!! Just kidding, Frazer. :-) Q1 What Dia. pinholes should I use for a) wide angle, and super wide angle images, and, what would be their corresponding fstops ?. Q2 What would be the appropriate distances between negative and pinhole for the above pinholes ?. The above question should probably be formulated in reversed order, in other words, you first want to know what focal lengths constitute super wide and wide, then what diameters should be used for them and finally what f/stops would they be. Wide: 120mm to 180mm Super Wide: anything under 120 In general, you could multiply a 35mm format focal length times 6 and that would be the equivalent to 6.5X8.5 format, I.E., 50mm is normal for 35mm formt, the equivalent for your half plate camera would be 50x6 = 300mm The so called optimum diameters would be given by: diameter in mm = 0.03679 x SQRT ( focal length in mm) SQRT stands for square root. F/stops could be found by dividing the focal length by the diameter of the pinhole you are using. The appropriate distance distance between pinhole and film plane is the same as the focal length. Download David Balihar's PinholeDesigner at http://www.pinhole.cz/en/pinholedesigner/ , excellent tool to help you with diameters, focal lengths, angles of view, f/stops, etc. Read my articles: http://members.rogers.com/penate/pinsize.htm http://members.rogers.com/penate/diameter.htm Peruse the resources page at Pinhole Visions http://www.???/resources/ and the one at the World Wide Pinhole Photography Day http://www.pinholeday.org/ Guillermo
Re: [pinhole-discussion] www.pinhole.cz
David, Great site and above all, outstanding and functional tool you are making available, I am talking about the PinholeDesigner, of course. Later I will pay your site a more thorough visit and let you know any other comment I have. Thanks. Guillermo - Original Message - From: David Balihar david.bali...@pinhole.cz I'd like to invite you to have a look at my new Internet pages www.pinhole.cz Apart from examples of photographs and pinhole cameras, you will also find several texts, for example, about the curious Dirkon paper pinhole camera, or the PinholeDesigner program which simplifies various calculations and enables you to save the zone plate in PDF format. I look forward to hearing your views and comments David Balihar
Re: [pinhole-discussion] 4x5 back needed
- Original Message - From: D. Hill zopp...@yahoo.com Does anyone have a spare 4x5 spring or grafloc back? I really need one, write me with what you want for it. I'd suggest you check eBay, I just did that myself and saw couple of backs or reducing backs that may be just what you want. I bought a wooden homegrown 11x14 spring back with GG, but have not been able to locate a holder for it, yet. I could let that spring back go for a price but that back is a bit bigger! than what you are looking for. Guillermo
Re: [pinhole-discussion] 4x5 film
On Thu, 17 Oct 2002, George L Smyth wrote: Not one of but the best book on the subject. g I've got a copy, but was suprised to hear that it was online (I wanted to do that long ago, but couldn't get permission). The above link I see as dead. Could you check it and let me know if the book is indeed online? Longtime ago I downloaded the book (lots of htmls and gifs) and have it in my disk drive, it is about 1.5MB ZIP compressed. There is also a PDF version here http://www.ushist.com/props/inc/albumen_salted_paper_reilly.pdf Guillermo
Re: [pinhole-discussion] weddings
- Original Message - From: eco...@aol.com Thanks for all the info. I could not get to 'stanford' site and the 'Zero' site did not give enough details. But I think a zone plate seems to be similar to a Fresnal Lens. If not, then further enlightenment is needed. Ellis Mark Iterrante mentioned my sites: Images: http://members.rogers.com/penate/ZP120.html Article on the subject: http://members.rogers.com/penate/zoneplate.html If something in the above article you don't understand of if you have any questions after having read it, pls post a question, either here or directly to my email address pen...@rogers.com Guillermo
Re: [pinhole-discussion] Pinhole enlarging
- Original Message - From: erick...@hickorytech.net The issue is the degree of enlargement. Enlarging 35mm to 4x6 increases the image area 16 times. Increasing a 4x5 to 16x20 increases the area only 4 times. 4x5 to 16x20 is also a 16X increase in area. You are right, the issue is the degree of enlargement and I'd add, the resolution you start with. Guillermo
Re: [pinhole-discussion] Pinhole enlarging
- Original Message - From: Uptown Gallery mur...@uptowngallery.org If one did MF (4x5 or 5x7) or LF (8x10) sheet film pinhole (and had an enlarger large enough), what are the prospects for enlarging? Murray, 4x5 5x7 were also LF last time a checked. I was very unhappy with 4x6 prints from 35mm pinhole. Could we see some of those results? Prospects of enlarging 4x5 and up, are excellent Prospects of enlarging 35mm format to up to 8x10 are fair to good (at least), but you have to shoot for the intended print size and properties. I wish I can show you some new results of enlarged 35mm negatives, but I haven't done pinhole or any other type of photography in ages :-( , last image I did was for a workshop I gave back in Nov/2001, the negative was a 35mm format size PAPER NEGATIVE taped inside this ugly camera: http://members.rogers.com/penate/cameras/14f.jpg (a disposable modified camera) and then enlarged/cropped to 6x6, here is the result: http://members.rogers.com/penate/doll6x6.jpg (the negative is shown at a greater magnification, than the 6x6 print itself). I'd call that a fair minus result, but bear in mind the original was a 35mm paper negative. This other example made back in 1996, is from a 35mm film negative using the same ugly camera above and enlarging it to about 8x10: http://members.rogers.com/penate/fire.html , I'd call that a fair plus to good result, obviously I am not talking about artistic merits but whether the image falls apart or not after enlarging it. The pinhole size, btw, was optimum for the focal length of that camera. Guillermo
Re: [pinhole-discussion] Polaroid Pack Film Mechanics?
- Original Message - From: Gordon J. Holtslander hol...@duke.usask.ca Polaroid makes a pinhole camera kit - I wonder if your film would work with it? Gordon: If I am not mistaken, the Pol-Pin takes 3.25x4.25 packs same as the ones the holder 405 uses. The famous pos-neg 665 is one example of those kinds of films. BTW, Michael, what about renting a Pol 550 back for a day and shooting away as if there is no tomorrow, until all boxes are gone!! Guillermo
Re: [pinhole-discussion] Polaroid Pack Film Mechanics?
Michael, This site may help you understand how a Polaroid pack works: http://www.theskeltons.org/polaroids/film.htm Guillermo - Original Message - From: michael_georg...@trendmicro.com Anyone have any experience with the mechanics of Polaroid pack film? = So, here I am with many, many boxes of Polaroid 553, Polapan ASA100 4x5 pack film, and no way to use it (yet). I can build a camera out of any damn thing, but a homemade Polaroid back presents a bit more of a challenge.
Re: [pinhole-discussion] Re: sheet film instead of photo paper
- Original Message - From: George L Smyth glsm...@yahoo.com There's nothing to stop you from using 4x5 sheets of paper with a 4x5 film back right? No...and you can enlarge them in a 4 x 5 enlarger...and in color too. leezy How would you enlarge paper via your enlarger? I taught a pinhole workshop for a local camera club this past Thursday. One of the exposures I made was a paper negative 35mm format!! which I then proceeded to enlarge to 6x6 size (a center portion of the negative) . I had no problem doing so and IMO it held up OK, even when using satin finish BW paper, glossy paper would give better results I'd assume. BTW, focusing on the grain of the photo paper was absolutely not a problem, it was very much like focusing on film grain. Never enlarged paper before, it is definitely doable. Guillermo
Re: [pinhole-discussion] DIana Camera Ebay
- Original Message - DIANA F Camera w/ lens cap http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItemitem=1299031604 Currently at $100USD. ? ok I don't understand... I know what you mean when you say I don't understand. And like you Andy, I know they are CULT-llector cameras and very IN with the so called ART communitynevertheless, I still is hard to understand that price for it!! Guillermo
Re: [pinhole-discussion] zone plate question
- Original Message - From: Richard M. Koolish kool...@bbn.com I'm not sure I would describe the workings of a zone plate this way. It doesn't matter where in the zone plate (or pinhole) the light passes through. It doesn't bend at one place and not in another. The way you think about a zone plate or pinhole is that every clear point acts like a spherical wave is generated there. Then from any point in the image plane, you add up all the contributions to the intensity at that position from all the individual contributing points of the zone plate or pinhole. Some waves will be in phase and reinforce each other, and some waves will be out of phase and destructively interfere. In the simple case of a pinhole, you discover, that a point source of light in a subject does not generate a true point of light at the film or even a simple disk, as if a beam of light came through. Instead, you get the clasic diffraction pattern of a point, i.e. a central disk (the Airy disk) surrounded by diffraction rings. Note that every aperture produces diffraction. Even the most perfect lens can't focus a point source into an image point. Normally you don't see this because the diffraction pattern is so small. An f/10 lens produces an Airy disk of only .0134 mm for green light. On the other hand, if you place a very small pinhole, say 50 microns (.05 mm) 100 mm away from the film and shine a red laser pointer at it, you will get a diffraction disk of about 3 mm in diameter. The zone plate has a lot of chromatic aberration. That is, it can't focus different colors of light at the same place. That's what causes the characteristic glow around bright objects in a zone plate photograph. One color may get focussed sharply and the others will get spread out into disks of various sizes around the sharp point. I can't speak to the issue of how much this changes with the number of rings in the zone plate since I haven't done any research on this. It would be an interesting and fairly easy experiment to try. Dick Koolish (kool...@bbn.com) ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.???/discussion/
Re: [pinhole-discussion] zone plate question
- Original Message - From: Kate Hudec hu...@rcn.com I was interested in Guillermo's recent post about the relationship between number of rings and zone plate image sharpness. I have a converted Lubitel with 75mm focal length. If I wanted a camera with MORE distortion (which I understand from Guillermo's post would also be a faster camera), would I need a camera with a longer or shorter focal length? Thanks in advance. Kate, I don't think I mentioned distortion in my post. A faster ZP has more clear rings, but that causes no distortion, the ZP camera still is free of linear distortion (at least). The increased number of clear rings increase the ratio noise/signal, tho. Noise is the light that reaches the film without having suffered diffraction, therefore do not contribute to the sharpness of the image, this is the light mostly responsible for the characteristic glow of a ZP image. Signal is the light that grazes the edges of the rings, suffer diffraction and is focused on the film plane, this light is the one resposible for the sharpness of the image. As far as getting distortion using longer or shorter focal length: Very wide angles of view are considered distorting because of the radically altered perspective compared to what we are used to see with our own eyes. If this is the kind of distortion you refer to, then, with a 6x6 film format Lubitel, you would need to have (IMO) the lens (pinhole or ZP) as least as close as 30mm from the film plane (closer would be better). I too have a modified Lubitel and I believe that even carving the front of the camera and recessing the lens, it'd be impossible to install the lens 30mm or less from the film plane w/o having vignetting caused by the viewing lens. If you want to sacrifice the composing help the viewing lens afford, then I think it may be doable but it'd easier if you get a cheaper 6x6 folder camera remove the bellows and modify it as pinhole/ZP. Something like this one I made: ftp://penate:athx2...@members.home.com/penate/cameras/12.jpg or this ftp://penate:athx2...@members.home.com/penate/cameras/6x6.jpg Hope it answers your questions. Guillermo
Re: [pinhole-discussion] zoneplates
- Original Message - From: Gordon J. Holtslander hol...@duke.usask.ca some quick questions for the zone plate experts. I am not an expert nor claim to be one, but your questions are right up my alley!! tedious. 1/2 hour for somewhat under-exposed negatives in direct afternoon sun. I want to speed this up somehow. How much faster does a zoneplate work than a pinhole on average? They are as fast as you want/make them to be, at a price tho. The more clear rings they have the faster they are, but the larger the noise/signal ratio. I want to try making a zone plate for this and other cameras. I was going to make the zone-plate on ortho film. I am wondering if its possible to make one master zone plate image and project from an enlarger, this image onto another sheet of ortho to scale it up or down make zoneplates for diffferent focal lengths. I think is doable, but I rather take pictures of a paper zoneplate at different distances with a 35mm SLR camera. I guess this depends upon whether or not the zoneplate for different focal lengths is proportional the same. Is it? Or is the ring relationship unique for each focal length? They are proportional. If B is the intended ZP focal length, A is the master ZP focal length and C is given by C = B/A then the ring diameters formula for Zoneplate B will be: D = Da * SQRT(C) where Da = ring diameter for master zoneplate. (complete explanation upon request) Is the sharpness of the zoneplate image governed by the number of rings? How close can one get the resolution of an image created with an ideal pinole diameter? Very close, just reduce the # of rings until you are satisfied with the sharpness, but then you are trading off fastness for sharpness My other question is has anyone had success creating and outputing these completely digitally -Is there a printer that can create a fine enough resolution image to make good zoneplates? I think Zernike makes his ZPs digitally, don't hold your breath waiting for him to contribute to this or any other thread, though (hope he proves me wrong!!). If I were to speculate. he may have a comercial image setter shop giving him a complete sheet of film with lots of ZPs of different focal lengths as output from a digital file he may produce with Corel or similar program. I never seen one (digitally produced ZP) but I guess they have jagged edges compared with analog made ZPs, that may or may not have any consecuences on the final image they produce. And no, I don't think a consumer or low end comercial printer would work. Should you find the opposite, let us know, pls. Guillermo
Re: [pinhole-discussion] 116 vs 616 film?
- Original Message - From: Guy Glorieux guy.glori...@sympatico.ca I just discovered that I have a Kodak 616 folder with negative sizes 4 1/4 x 2 1/2 that is virtually new. Inside it says to use 616 format. Can I put in 116 format or will I run into the same problems as 120 vs 620? Same problem, Guy. 116 preceded 616. The latter being the same size film as the 116 (2.5), was made with smaller diameter spool to fit thinner cameras. 616 still is available from places selling film for classic cameras. If you already have 116 film and have two 616 spools, re-spooling your 1116 on 616 is an option. too. Guillermo
Re: [pinhole-discussion] slit cameras?
- Original Message - From: Tom Miller twmil...@mr.net Also, do you have any explanation why in some slit configurations there is a lot of banding (thin black lines) forming over the image? This quote is from Jim Moninger's article in the Pinhole Journal vol. 15 #1 : These are apparently caused by the light rays / waves with form the two separate images becoming out of phase with one another. Tom Not just out of phase but 180 degrees from each other. This -perhaps- are regions where light (wave) diffracted by one slit is at its maximum peak (+) and light (wave) diffracted by the other slit not just overlaps the former but happens to be at its lowest peak (-), the net effect is darkness, light from one slit canceling out with light from the other slit, weird, eh? This BTW, is called Destructive Interference. Guillermo
Re: [pinhole-discussion] 127 film?
- Original Message - From: Andy Schmitt aschm...@warwick.net Darn...I knew I should have paid more attention in German class... Isn't Schmitt a German surname, Andy? can't speak German? shame, shame :-) The MACOPHOTO films look real interesting. Hopefully they will be able to point me to an English translation of the info .pdf the pricing isn't too bad. There is this within-same-continent alternative. also: http://www.frugalphotographer.com/index.htm They even have 126 film for a quick pinhole camera set-up. Guillermo
Re: [pinhole-discussion] Cool News
- Original Message - From: Gordy Emery geme...@hotmail.com To: pinhole-discussion@p at ??? Sent: Monday, November 05, 2001 7:49 AM Subject: Re: [pinhole-discussion] Cool News WHAT IS THIS? YAHOO! YAHOO: Yet Another Hierarchical Officious/ Obstreperous/ Odiferous/ Organized Oracle. It also NOW is used as a shout of joy, perhaps in a similar way you would say HURRA. Guillermo
Re: [pinhole-discussion] Back again...
- Original Message - From: Erich fot...@rz-online.de well welcome backToyo 8x10 is literally a pain in the bones.. muscles... . Eric, You may want to buy a wooden or metal 8x10 back (I see them at eBay frequently) and just make a wooden box or boxes for it. Willkommen zurück zu der pinhole liste Guillermo
Re: [pinhole-discussion] f stops
- Original Message - From: Andy Schmitt aschm...@warwick.net ow now done get like that... I was just kidding...tho not about the great explaination part...I'll use it with my class next summer 8o) Hope your back gets better... Btw are you still making precision PH's for others? Only when I have WY too much time! :-)) Guillermo
Re: [pinhole-discussion] f stops
- Original Message - From: Andy Schmitt aschm...@warwick.net Gill you have WAY too much time on your hands.. but a great explaination..I'll save this one thanks I am sorry Andy, was off, back was acting up, weather lousy, no reason to go out. From now on I will only reply when I don't have WAAAY too much time in my hands, so answers are as un-prolific as possible. Guillermo
Re: [pinhole-discussion] f stops
- Original Message - From: TSHACK tsh...@silver-bayou.com How would I join the cameramakers list? Is that a newsgroup, or an email list? Email list, similar to our beloved pinhole list. Here is some info on it: Cameramakers mailing list cameramak...@rmp.opusis.com http://rmp.opusis.com/mailman/listinfo/cameramakers Guillermo
Re: [pinhole-discussion] f stops
- Original Message - From: Gregg Kemp gregg.k...@sas.com To: pinhole-discussion@p at ??? Sent: Tuesday, October 30, 2001 1:02 PM Subject: RE: [pinhole-discussion] f stops I wrote to Philip asking if he was having a problem with his mail and if I could help. I haven't gotten a reply, but noticed he continues to send empty messages. He's also sending blank msgs to the cameramakers list, also and lots of them! Guillermo
Re: [pinhole-discussion] f stops
- Original Message - From: ragowaring ragowar...@btinternet.com Anyway, enough of an introduction; could anyone please tell me how to calculate the natural progression of f stops doubling exposure from one number to the next, or post a list of these. They follow a geometric progression that make the f/stops increase by a factor of square root of 2 Need a more complete explanation? let me know. Guillermo
Re: [pinhole-discussion] Zone Plate Focus stringency
- Original Message - From: TSHACK tsh...@silver-bayou.com That was going to be my question. When you focus a lens using a ground glass, you are just making coincide the -ideally- flat image the lens is projecting with the surface of the ground glass, if you remove the ground glass, your eyes can't see the image, but the image is still there focused in the air. If you take a loupe and make its base coincide with that image in the air, in other words, with the Aerial Image, you will then see the the exact same image your film will see. This is best seen in axis with the lens. If your camera has GG, remove it an install a piece of clear glass, this will allow you to rest the loupe steady, otherwise, you will have to rely on your steady hand. Again, you will probably be surpriced of what you see. Guillermo
Re: [pinhole-discussion] Zone Plate Focus stringency
- Original Message - From: TSHACK tsh...@silver-bayou.com I congratulate you folks who can focus one of these things through the viewfinder. I pulled out my Crown Graphic, slapped on the reflex viewer, tried focusing on a light source, tried focusing on a subject outside, and I really couldn't tell any difference except at the extremes. Maybe if I use a loupe. Maybe not. Although I do not recommend focusing of the zoneplate every time you make an exposure, I do recommend you focus it ONCE so you find out (if you wish) the actual focal length of it. To do it, aim your camera to a light source (light bulb for instance) or well illuminated object and focus on the aerial image, rather than on the ground glass. You will be surprised how good is the image a ZP produces. And yes, use a loupe. Guillermo
Re: [pinhole-discussion] Zone Plate Focus stringency
- Original Message - From: Richard M. Koolish kool...@bbn.com A zone plate focusses like a lens so you should adjust the focus for objects at different distances. On the other hand, they tend to have large f numbers (like f/32) so they have large depth of field. They are also hard to focus because they are so dim. Right. And if you ever decide to focus them, it is best to do it on the aerial image. My suggestion: don't bother focusing, mount it at a distance from the fillm plane equal or as close to the focal length it was made for and that should be sufficient to get good results. BTW, I don't think making ZP faster than f/64 is a good thing. A f/32 ZP would require a large number of rings/zones and that augments the noise/signal ratio considerably. For instance, a 90mm ZP f/32 would need 79 rings/zones (total), f/64 would just need 19. Guillermo
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
- Original Message - From: Gregg Kemp gregg.kemp@??? Guillermo, I don't remember ever seeing your correction formula before. Is that theoretical, or have you tested it? Theoretical, Gregg, as I haven't done any close up work myself. For those (few) people interested in were that correction factor comes from, here it is: ** Pinhole is in most ways, not different than glass lens photography. The lens conjugate equation is: 1 / F = 1 / I + 1 / O where I = distance pinhole to Image plane; F = Focal length and O = distance pinhole to Object being photographed. We can simplify that to: F = I x O / I + O When the Object being photographed is at infinity ( O = infinity ): I + O = O therefore the formula F = I x O / I + O becomes: F = I x O / O and that becomes F = I In other words, when the Object is far away (more than 10 times the distance pinhole to film, in practical terms), the Focal length of the camera is equal to the distance pinhole to film plane. Now, when the Object being photographed is close to the pinhole lens (less than 10 times the distance pinhole to film, in practical terms), the Focal length of the camera is given by (as I stated above): F = I x O / I + O For close up work, then, F has to be substituted (in any of the formulas for optimum pinhole size) by: I x O / I + O For instance, the formula I use is: D = 0.0073 x SQRT( F ) where D = pinhole diameter in inches; F=pinhole camera focal length and SQRT stands for square root of For close up work that formula becomes: D = 0.0073 x SQRT( I x O / I + O ) As I said before, F = I for infinity, therefore I can write the infinity formula as D = 0.0073 x SQRT( I ) Base on that, I can also rewrite the close-up formula as: D = 0.0073 x SQRT( I ) x SQRT ( O / I + O ) There you have the correction factor: SQRT ( O / I + O ) BTW, there are many formulas for optimum pinhole size but all have within them SQRT(F), therefore, the above correction factor should apply fine to all of them. Let's see an example: Our pinhole camera has a distance pinhole to film I = 8 and the Object being photographed is O = 12 away from the pinhole, what size of pinhole is the optimum to use: The optimum pinhole size for infinity is: D = 0.0073 x SQRT ( 8 ) D = 0.020 (aprox) Correction factor is: SQRT ( 12 / 8 + 12 ) Correction factor is: 0.774 Pinhole size for close up work (object 12 from pinhole lens) D = 0.020 * 0.774 D = 0.0155 BTW, all the above is nothing but a sort of bellows correction. For people with mathfobia but that have read this msg up to this point, here are some corrections factor based on how many times the camera pinhole-film distance the object is away from the pinhole lens: less than 10 times = correction factor = 0.95 less than 9 times = correction factor = 0.94 less than 8 times = correction factor = 0.94 less than 7 times = correction factor = 0.93 less than 6 times = correction factor = 0.92 less than 5 times = correction factor = 0.91 less than 4 times = correction factor = 0.89 less than 3 times = correction factor = 0.86 less than 2 times = correction factor = 0.81 less than 1 times = correction factor = 0.70 less than 0.5 times = correction factor = 0.57 Another couple of formulas than may help the original's question poster are: Magnification M = I / O Therefore the Correction factor can also be written as: Correction factor = SQRT [ 1 / (M+1) ] So for instance, if she wanted to photograph an object 2 tall with a camera having 8 between pinhole and film and get a magnification of 2X, she will need to position the object at a distance: O = I / M = 8 / 2 = 4 O = 4 inches and the pinhole size (diameter) should be: D = 0.0073 SQRT(8) * SQRT[ 1 / (2+1)] D = 0.012 The image size will be 4 and therefore the minimum format size needed is 4x5 (portrait) or perhaps -better- 5x7 to allow for some cropping. Guillermo
Re: [pinhole-discussion] Micro or macro photo with pinhole photo
- Original Message - From: Richard Heather rheat...@slonet.org See the pinhole size calculator at Pinhole Visions: (Larry Bullis) http://www.???/resources/articles/makingholes.php Guillermo's page: http://members.home.net/penate/pinsize.htm There are various calculations that are based on the assumption that you will shoot at infinity. For close up views a smaller hole will give sharper results. For close up work just multiply your optimum pinhole size, obtained with any of the formulas available out there, by the correction factor: Correction factor = SQRT ( O / I + O ) where O = distance pinhole lens to object being photographed and I = distance pinhole lens to film SQRT stands for square root of Guillermo
Re: [pinhole-discussion] new list moderator
- Original Message - From: Kosinski Family zin...@telenet.net Guy's the GUY! best of luck He'll surely need it to deal with us bunch of trouble people! BTW, there are some names I am sure not everybody nows how to pronounce them, like mine for instance: Guillermo is pronounced Gih - jer - moh and I am pretty sure Guy's name is pronounced: Gih or Gi as in Gilligan, correct me if I am wrong, Guy. Guillermo
Re: [pinhole-discussion] self-intro/printmaking
- Original Message - From: Eric S. Theise mat...@cyberwerks.com I'm a sysadmin and web designer and yes I use vi Here is for all of you VI lovers: (will never do it again Gregg, I promise!) ADICTED TO VI You press the keys with no effect, Your mode is not correct. The screen blurs, your fingers shake; You forgot to press escape. Can't insert, can't delete, Cursor keys won't repeat. You try to quit, but can't leave, An extra bang is all you need. You think it's neat to type an a or an i-- Oh yeah? You won't look at emacs, no you'd just rather die You know you're gonna have to face it; You're addicted to vi! You edit files one at a time; That doesn't seem too out of line? You don't think of keys to bind-- A meta key would blow your mind. H, J, K, L? You're not annoyed? Expressions must be a Joy! Just press f, or is it t? Maybe n, or just g? Oh--You think it's neat to type an a or an i-- Oh yeah? You won't look at emacs, no you'd just rather die You know you're gonna have to face it; You're addicted to vi! Might as well face it, You're addicted to vi! You press the keys without effect, Your life is now a wreck. What a waste! Such a shame! And all you have is vi to blame. Oh--You think it's neat to type an a or an i-- Oh yeah? You won't look at emacs, no you'd just rather die You know you're gonna have to face it; You're addicted to vi! Might as well face it, You're addicted to vi! Copyright 1989, by Chuck Musciano. All Rights Reserved
Re: [pinhole-discussion] piezography?
- Original Message - From: Jeff Dilcher r...@hiddenworld.net I have heard people refer to piezography when referring to printing from a computer. Is this just a fancy term for inkjet printing? The fancy name is Gicleé and not all the Gicleé prints are printed using Piezography system. Read about Piezography from the horse's mouth at piezography.com Guillermo
Re: [pinhole-discussion] email address of Ahmet Selim Sabuncu?
- Original Message - From: Lukas Werth lukas.we...@rz.hu-berlin.de Does anybody know the email address of Ahmet Selim Sabuncu? I have just visited his website which I found *very* impressive, http://www.pinhole-photo.com/ and I would like to get into concact with the photographer, but the link to his email address does not seem to work. Lukas, the links for ORDER and CONTACT have not been coded properly. His/her email address seems to be i...@pinhole-photo.com give it a try. Guillermo
Re: [pinhole-discussion] Pintoid and Celestial Seasonings Teas
- becoming poor by buying all kinds of objects ( and even ...anything) not for the merchandise itself but just for the container, Children very often like playing better with the packing material rather than we the toy that came into it. The name of the game is FUN and is a child have lots of it with a simple cardboard box, why shouldn't we! I don't know if it hapens to you guys/gals, but when my wife see me seeing any container for more than few seconds she ask me: Another pinhole camera, eh? (not that she minds :-). Guillermo
[pinhole-discussion] Pinhole camera plan+instructions
I know many here subscribe to the cameramakers list, but for those who don't, here is the copy of a recent message: I found this while surfing around today. It's free instructions and plans for a wooden pinhole camera that takes a 4x5 sheet film holder. http://www.popularwoodworking.com/features/fea.asp?id=1048 Guillermo
Re: [pinhole-discussion] Determining exposure beyond.....................
- Original Message - From: Ricardo Wildberger Lisboa wildber...@svn.com.br Can I find that Ilford reciprocity failure table on the web? If it is Ilford film tables you are looking for, yes you can find them at www.ilford.com If what you are looking for is reciprocity tables for ilford paper, you can find the table I use in an article I wrote about pinhole exposures: http://members.home.com/penate/pinhole.html (link is almost at the end of the page) ? Is there a similar table for T-max 100 ? That one is at www.kodak.com Reciprocity failure is really a problem. If you are into pinholing, just learn to live with it! or shoot Ilford delta 3200 and push it to 25000, it will give you exposures of 1/100th of a sec under sunny skies with a pinhole camera f/256.forget about the electric tape shutter, though! :-) What if I'm working with lith film for half tone development later on ? Thank you for any help. You got me here, my guess is that reciprocity may be close to what for ilford paper emulsion is, but that is just a guess. Guillermo
Re: [pinhole-discussion] Re: new to this list
- Original Message - From: Andy Schmitt aschm...@warwick.net so you've mounted your PH's on the inside.I've been using 35mm slide holders for pretty much the same thing. what diameter is your composing washer? This was something I was thinking of trying. Washer hole is 1/8, image is very fuzzy, but I am interested in recognizing shapes not in details. Guillermo
Re: [pinhole-discussion] Polaroid Japan Introduces Pin-hole Camera Kit
- Original Message - From: Guy Glorieux guy.glori...@sympatico.ca I just read your release on Pinhole Visions. Is this you behind this initiative? I thought that there was too much reciprocity/color shift problems with polaroid to be really successful material for pinhole. When are we going to see it in Canada? SEE IT that's as far I'd go, the concept is very interesting but I can't get myself to pay $100 for it. I bought a Polaroid back accepting 600 film at eBay couple of weeks ago for $10 with the intention to transform it into a polaroid pinhole camera, eventually. Nevertheless, I'd like to tell my Japanese friends or anybody else: Whenever in doubt, Go for it!, I don't have doubts, though!. Guillermo
Re: [pinhole-discussion] Pintoids
- Original Message - From: Markus Birsfelder b...@active.ch Hello Marcy Your pictures are great and I would like to try making some of my own. Being a Swiss, I have not the faintest idea what an Altoid container is. Could you give me a hint. Here is a hint: altoids.com Isn't it the web wonderful!! Guillermo
Re: [pinhole-discussion] Pintoids
- Original Message - From: Marcy Merrill ma...@merrillphoto.com made over one hundred Pintoids. I knew about people eating Quaker cereal like crazy to have pinhole camera material, but 100 Altoid boxes is a lot of mint! :-) Guillermo
Re: [pinhole-discussion] Really-large format pinhole
- Original Message - From: Guy Glorieux guy.glori...@sympatico.ca For anyone interested in really-large format pinhole camera making, there is a 20x24 bellows for sale on eBay. (US only) Current bid is at $66.00... This beats you 6x9 format, Guillermo! ...-:)) You won't believe it but I got one of those. Some years ago I bought at an auction a vertical copy camera, my main interest was 4 Schneider lenses it had (3 of them G-CLARON), I removed the lenses, the bellows and the vacumm easel+pump. Sold one of the lenses and the Vacumm easel+pump for more than what I paid for the whole camera! Couldn't keep the camera due to lack of space. One of this days I will make something out of it. Guillermo
Re: [pinhole-discussion] Re: new to this list
- Original Message - From: Guy Glorieux guy.glori...@sympatico.ca http://members.home.com/penate/cameras/6x6.jpg Nice piece, Guillermo. How does 36mm on 6x6 compare with 35mm format focals? Would it be around 20mm? That is correct. (18.35mm to be more exact). I like the way you've managed to keep the shutter and cable release. I think I'm going to search for an Agfa on eBay... -:)) I am now looking for a 6x9! Don't outbid me pls!! :-) On vignetting, I myself have come to build vignetting as a pictorial component of my images. Although I have not been able to get real vignetting in any of my cameras, even with the 14mm (35mm format) I don't get too much (I guess my pinhole are just too good! ;-), I really like the effect in some circumstances. But, IMO there is a difference between mechanical vignetting and optical one. The kind of vignetting I am talking about on this camera was the mechanical one, sort of like when the filter ring gets in your picture when using wide angle lenses. Guillermo
Re: [pinhole-discussion] Re: new to this list
- Original Message - From: Andy Schmitt aschm...@warwick.net Neat camera Gill...even a real back on it. What is the focal length do you get much vinetting with it? Andy, I have had good luck in finding real backs, that 8x10 cost me like $7 US, it is metal and has two thumbscrews that allow me to flip it to vertical or horizontal composition. At the front I installed a filter ring that allows me to use filter on it. Focal length is 90mm, no real vignetting. Here is the back alone: http://members.home.com/penate/camera/back.JPG Here is the back sans GG: http://members.home.com/penate/camera/backback.JPG See the square in the middle, it is a flat magnet. I mount a small washer that I use as my composing lens and then I mount the pinhole (non-magnetic) and keep it in place by putting a big (magnetic) washer on top. Since I needed to have easy access I removed the GG and mounted it to a cardboard frame, I also mounted a plastic fresnel reading lens on the GG, that helps me have a brighter image: http://members.home.com/penate/camera/fresnel.JPG Here are couple of pictures showing the front of the camera and the filter ring, you can also see the composing aperture (AKA washer): http://members.home.com/penate/camera/front.JPG http://members.home.com/penate/camera/filter.JPG I also have a very nice 5x7 metal back I bought for $10! at a photo fair (some vendors have no idea what they are selling!! I am not complaining though!). I have yet to turn it into a pinhole camera. Guillermo
Re: [pinhole-discussion] Re: new to this list
- Original Message - From: tricks...@aol.com Weird. The only experience I have ever had with a pinhole was in my high school photography class. We made shoebox pinholes, painted them entirely black inside with a small hole about the size of a pencil hole on the opposite side of the RC based paper. For a shutter we just covered the hole with a paper and tape and just lifted it up for about a 10 to 20 sec exposure and then closed it. We then developed the paper. My first pinhole image turned out pretty good but it didn't have a lot of contrast to it. From what I'm hearing it sounds like you guys have more technological forms of a pinhole camera like actually using film in it. Most people start shooting BW paper, but there are times when you would like to have the luxury of making lots of exposures. Having lots of shoe boxes loaded with paper is a way, having pinhole cameras that take film (rolls: 35mm or 120, or even sheet film 4x5, 8x10, etc) is a less bulky one!. BTW, film holders for 4x5 and above also take BW of the corresponding sizes. Making your own film winding mechanism is not feasible for many of us, so usually we recur to modify cameras. These are some I have modified (and that still have with me!): A disposable 35mm plastic camera made to be a 14mm pinhole camera, shutter is a piece of electric tape: http://members.home.com/penate/cameras/14f.jpg A 35mm format camera bought for a few bucks ($3.50 US I think) and converted to a pinhole camera, shutter is a piece of foam: http://members.home.com/penate/cameras/12.jpg My latest one, just finished it yesterday!, an Agfa 6x6 folder purchased at eBay for $9 converted to a 36mm pinhole camera, I still use the shutter that came with the camera, but removed some of the front stuff to avoid vignetting. http://members.home.com/penate/cameras/6x6.jpg Finally, this is a Pinhole Nikon bodycap I made by drilling a hole and taping a pinhole at the back of it, I use that with my Nikon camera (obviously). http://members.home.com/penate/bcap_files/cap.jpg I guess that is another way to do it. I'm sort of clueless as to make one. Hope the above give you some ideas. The words you guys use are somewhat unfamiliar to me like pinhole/zone photography . You know what pinhole is. Zone Plate photography is a relative to pinhole photography, you can read an explanation about it here: http://members.home.com/penate/pinhole.html (look for the article at the bottom of the page. There is also a link to some examples of zoneplate images. I'm assuming that 4x5 is a large format camera? How do you make a good pinhole camera? What do you guys use? Yes 4x5 refers to large format cameras, it is relatively easy, though, to construct a camera that uses 4x5 film holders, some of the list members have done it. I made one that takes 8x10 film holders. Here is a picture as seen fron the rear: http://members.home.com/penate/camera/camera.JPG As far as how to make a good pinhole camera, you'll have to define what good is for you, first. Guillermo
Re: [pinhole-discussion] internal / international
- Original Message - From: ethereal art ethereal...@mindspring.com Since the Zero 2000 is made in Japan In the Hong Kong prefecture, to be more exact!! ;-) Guillermo
Re: [pinhole-discussion] 4 x 5 questions
- Original Message - From: Chris Harris cpharrisph...@hotmail.com First, I can't see the image without a lupe. This makes composing on the ground glass impossible. What f/stop is your zoneplate? if it were f/90 or f/64 (better) you shouldn't have problems composing your image, you must use a dark cloth though. You mentioned fresnel, that would also help, to see its effect before you buy an expensive one, buy one of those plastics reading fresnel lens you can buy at bus.depot, office depot, etc, they are just few bucks each. cut it to fit the back of your ground glass. I should mention that I'm used to pinhole cameras without viewfinders, but I thought I'd have the luxury of seeing an image on the 4 x 5 ground glass. If you want to see an image on the GG with a pinhole lens, have two pinholes, actually, 1 pinhole and one nailhole, use the latter to compose and the pinhole to make the exposure. The second problem is that the camera seems to be in focus through a wide range of focal lengths. I can't see any difference between the focus quality at 150mm (which the zone plate is designed for) and, say, 170mm. The magnification changes, but the focus stays the same. I can set the focus at infinity by measuring the distance from the film plane to the zone plate. However, the fine adjustments of focusing with tilts and swings seem at this point impossible. My suggestion is that you find the actual focal length of your zoneplate once and then use that distance everytime after. If you want to focus a zoneplate, is almost a must to do it viewing the aerial image and not the GG. BTW, you'll probably be amazed at how nice the aerial image projected by a zoneplate looks. Guillermo
Re: [pinhole-discussion] 4 x 5 questions
- Original Message - From: Jeff Dilcher r...@hiddenworld.net Stick man is your beautiful model (I have to much time on my hands today). F / |\ / | \ / |\ / O | B}P \+/ |/ \ ^ | / \ / \ |/ \ \ F One of the best ASCII art I ever seen! undoubtedly has Cubism influence. :-) Guillermo
Re: [pinhole-discussion] Determining exposure beyond.....................
- Original Message - From: Rune Tallaksen tall...@alfanett.no Can anybody help me with how to determine exposure when correcting for resiprosity failure when the measured esposuretime exceeds that of the table from the filmvendor? For instance when using Ilford HP5 Plus, the film data sheet gives the added time for resiprosity failure until initial measured 35 secs(corrected for pinhole f stop). How can I calculate the correct exposure time beyond this point? Tiral and error until now has not been satisfactory for me. One way to do it is by extrapolating the curve Ilford is giving you. You can do that mathematically or graphically. I usually do it graphically. Take the Ilford curve and reproduce it on a piece of paper, extend the X or horizontal axis to read the maximum uncorrected time you want and then extend the curve with pencil trying to follow the same tendency, then is just a matter of extending the Y axis and graduating both axis. I just did that very quickly and the resulting extended curve gives me the following values, for 60, 90 and 120 secs of uncorrected exposure: 60 secs uncorrected = 475 secs corrected 90 secs = 925 secs 120 secs = 1900 secs Once you have the extrapolated curve, use it and if you get consistently somewhat overexposed film, that means the curve was done a bit to steep. If film is underexposed consistently then the curve needs to be re-done a little more steeper. One thing for sure, extrapolating the curve would give you better reciprocity corrections than trial and error. Hope it helps. Guillermo
