Re: [pinhole-discussion] coverage
- Original Message - From: Richard Koolish kool...@alum.mit.edu Cameras that are half cylinders or whole cylinders, like the classic oatmeal box cameras have different falloff patterns. Half cylindrical cameras have a fall off of very close to just Cosine of the angle, as a result, a 120° total angle of view pinhole camera would have a fall off of just 1 stop instead of 4 stops, very dramatic improvement. Anyone wanting virtually no fall off, should consider half cylindrical cameras. Guillermo
Re: [pinhole-discussion] polaroid pinhole question
- Original Message - From: Trent Dowler tdow...@grnco.net Perhaps I've missed it, but why does the Polaroid film packs produce strong magenta tones? Could it be improper developing time? Reciprocity failure.
Re: [pinhole-discussion] Sized needles
- Original Message - From: Becky Ramotowski becks...@cotse.net If I drill my own pinhole and want the smallest possible hole with the number 15 needle, do I understand correctly to just get the point through, then sand the rough edge and that's the end of it? I'd do 2 more things: take the needle and insert its tip into the hole, rotate the needle couple of times, do it gently, the aim is not to make the hole bigger but to clean any burrs the sand paper -usually- leaves at the edge of the hole. Then apply a burst of air to the hole. Guillermo
Re: [pinhole-discussion] WPPD2003
- Original Message - From: Wally Wolfgang Thoma-Schuermans th...@pandora.be Shelley, I think you didn't get Rosanne's earlier posting. This is a technical discussion and not a chat box. Sorry for being rude, I have been with this list since almost its inception, the above post does not represent what this list has been and is about. Anytime you have to apologize by saying you are sorry, I'd suggest you stop, don't press Send, go back and delete the very same thing you are apologizing for. That's the beauty of written communication, it gives us that chance. I wish I could do that with things I have verbally said in the past! Your message, Taco, was totally uncalled for, Shelley's message is absolutely in tune with this list's reason to exist, IMO. On the other hand, this list has 2 moderators let's leave the task of putting us back on topic to them. Guillermo
Re: [pinhole-discussion] Zone plates pinhole sieves
- Original Message - From: Wally Wolfgang Thoma-Schuermans th...@pandora.be Very interesting. I have a Lubitel myself (bought in a second hand shop in Prague for 10 USD) that I wanted to use for serious 6x6 work, but it leaks light like hell, so why not transform it. Can you give me details (how to open the lens) etc. Can I still use the shutter? greetings, Taco Taco, It is actually very easy, the shutter/lens assembly come off by removing the lock nut at the rear and accessed thru the inside of the camera, use a screwdriver to turn the nut, once the assembly is off the camera, unscrew the very front of the lens, then you'll see another small lens also part of the front lens elements, this one is removed by removing a C clip. At the rear of the shutter there is another C clip that allow you to remove the rear lens element. I mount the new aperture in place of the rear element, this place the ZP, etc. 65mm or so from the film plane. I first mount the ZP on a plastic circle that fits snugly on the rear of the shutter, I usually use plastic from one of those 35mm canister's cap. Recently I have decided I will not use this cameras with their original glass, so I being making a hole in the center of the glass rear element and mount the aperture there. Guillermo
Re: [pinhole-discussion] pinhole light falloff vs. circle of coverage question
- Original Message - From: Uptown Gallery mur...@uptowngallery.org If one set up a 4x5 bellows camera for pinhole with an appropriate pinhole for double extension (say 300 mm), placed the bellows at 300 mm but used a 4 x 5 filmholder, would that place the worst of the edge falloff outside the 4x5 image? It seems to me that this would work, at least to reduce the effect somewhat. Although fall off, technically speaking, starts right as soon as we depart from the very center of the filmplane, it'll not be noticeable until a distance around half the diagonal of the image format. In other words, as long as your focal length is equal or greater than what it is considered the normal focal length for the format, the fall off can be disregarded. As a matter of fact, if you are enlarging a negative made with a 150mm focal length pinhole, and you use a 150mm enlarging lens to do it, the fall off in the negative will be corrected by the fall off of the enlarging lens. This is one of those cases in which 2 wrongs make a right!! Guillermo
Re: [pinhole-discussion] new to list/pinhole photography
Shelley, Pinhole photography is in technical aspects not different than glass lens photography. Focal length, aperture (not aperture size), exposure, angle of view, light fall off at the edges of film, reciprocity corrections, etc., are all concepts that function the same whether the lens is a pinhole or a glass lens. Based on the above, it makes sense that the program have you doing pinhole in 102 rather than in 101 as the latter course (hopefully) included all of those concepts. If you do a google search you are going to find several sites that have tables with needle sizes and their diameters, George Smith's being one of them http://mywebpages.comcast.net/hmpi/Pinhole/Articles/Aperture/pin_aper.htm , but if I were you and had access to a flat bed scanner, I would use it to measure its actual size. This small article I wrote tells you how to achieve that: http://members.rogers.com/penate/diameter.htm Guillermo - Original Message - From: Rauch, Shelley ra...@yorkcounty.gov Things not discussed: focal length, aperture size, exposure. I've glossed about on the internet and read some good articles on all of these. I'm currently trying to figure out what my aperture size is. I used, the teacher thinks, a #10 sewing needle to create the hole. Is there an 'average' size for this sort of needle? I'm going to be experimenting tomorrow morning, but the darkroom will only be open for a few hours tomorrow afternoon, then closed again until Tuesday. I'd like to avoid wasting paper. Any advice about my aperture, exposures, or anything I'm not thinking to ask? Thanks... from a very frustrated student... Shelley C. Rauch Acquisitions Dept. (757)890-5116 Tabb-York County Public Library 100 Long Green Blvd. Yorktown, VA 23693-4138 ___ 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] I need some e-mail addresses please!
- Original Message - From: Tom Lindsay pinhole-...@juno.com Hi, it's Tom Lindsay here and I need to have those people who know me send me your e-mail addresses so I can contact you directly. I'm at my honeys'' house and don't have all the addresses that I would like to have. While your not too busy, please take a look at my new exhibit http://www.???/exhibit/cancer and please sign the guest book too. The correct URL to Tom's essay is: http://www.???/exhibits/cancer I have not finished reading it, but the 4 or 5 pages I have seen and read indicate that it is something out of the ordinary, in fact it is an extraordinary essay. DO NOT MISS IT. Guillermo
Re: [pinhole-discussion] disposible camera
- Original Message - From: bendur...@aol.com I recently got a copy of the disposible camera handout, thank you very much. But I was at the gallery where I work the other day, taking a disposible cameera apart. And one of the security guards dave asked me what I was doing, when I said I was making a pinhole camera, he thought I was perhaps some king of pervert. King of perverts! that's really funny. Does anyone else have any stories of pinhole-related misunderstanding. Yeah, I once was doing some pinholing inside the beautiful building of Trinity College at the University of Toronto and the, yes you guessed, security guard told me not to continue because he thought my 4x5 made out of scrap baseboard moulding was a professional camera! I was able to use my Nikon SLR w/o problems tho. Guillermo
Re: [pinhole-discussion] f64,f90,f128?...
Andrew, f/stops progress by a factor of 1.414 which is the square root of 2, therefore, the numerical value of f/stops double every other stop. If we start at f/11 (we could have started with any f/stop), the next one is f/16, since they double every other stop, the progression would go like this: 1 (half 2) 1.4 (half 2.8 2 (half 4) 2.8 (half 5.6) 4 (half 8) 5.6 (half 11 or so!!) 8 (half 16) 11 --known starting consecutive f/stops 16 --known starting consecutive f/stops 22 (double 11) 32 (double 16) 45 (double 22...or so!!) 64 (double 32) 90 (double 45) 128 (double 64) 180 (double 90) 256 (double 128) .add infinitum So, if you know 2 consecutive full f/stops values, you can find out any other full f/stop in the progression. Guillermo - Original Message - From: Andrew Amundsen a...@tcinternet.net Can anyone help? What's the proper progression of f-stops above f90? Is f128 next and tell a couple more if you have the info at your fingertips. I've picked up a Finney Pinhole Bodycap for my Leica M. It's listed as a 30mm, approx. f128 and my Minolta meter goes to f90. So is f128 the next f-stop in the natural progression of reciprocity? Twice as small? If not someone please correct me! Thanks for the help, Andrew Amundsen
Re: [pinhole-discussion] 35 mm pinhole camera
- Original Message - From: Zami Schwartzman zami...@netvision.net.il the buurs on the oposit side had to be very carefuly treated with no. 400 sandpaper to get a perfect hole . Although not a sraight forward job , I can get perfect holes as small as 0.05 mm diameter FYI, such small pinhole would be optimum for a camera with a 1.85mm focal length!! A bit impractical, if you ask me!! I experimented with a 0.1 mm hole , got some good close up pictures well exposed with Kodak gold 400 ASA( using f: 120 on the light meter ) but the results are quite out of focus on 10x15 prints . -Your f/stop should be f/280 and not f/120. -f/stop is given by dividing the focal length by the pinhole diameter (28/0.1 = 280) -As pointed out by erick...@hickorytech.net, you should be using a pinhole 0.00784 which is equivalent to 0.2mm. The 0.1mm pinhole is producing too much diffraction. -If you want relatively sharp 10x15 size results, I would suggest you shoot medium format or larger. I wander if going further to a 0.05 hole will worth the panelty in the f number . Only if you could mount that pinhole about 2mm from the film plane. The resulting image, BTW, would be a circular image no bigger than some 10mm in diameter. Is there an optimun hole size for best sharpness ? or is it the smaller the better. Take a look to this http://members.rogers.com/penate/pinsize.htm Guillermo
Re: [pinhole-discussion] polga
300 US bucks for a Polga!!? Imaging how much a Piana could go for! Guillermo (who do know Dianas are not in production anymore)
Re: [pinhole-discussion] 4 questions from a beginner
- Original Message - From: Bre Pettis pett...@yahoo.com Question 1 I've got a .013 needle hole and 1#34; from the hole to the film. I've got it loaded with 400 speed bamp;w film. How long should I try for an exposure on a sunny day? Am I right in gauging the f stop at f/77? I've got a light meter, should I use it and should I make any adjustment for using a pinhole? If your pinhole is actually 0.013, yes f/77 is your f/stop. Once you know the f/stop and speed of film, when it comes to find the exposure time, it is irrelevant what camera you have (IE: cardboard pinhole or Hasselblad) as well as irrelevant is which lens you are using (IE: a Carl Zeiss or a dirt cheap pinhole lens) and what's the focal length of that lens. So if you got a light meter, use it business as usual. BTW, f/77 is equal to f/64 +1/2 stop, if I were you, I'd approximate that to f/90. If so, Sunny/16 says that under bright sunny skies and using ISO-400, exposure should be f/16 and 1/400 secs, therefore for your f/90 pinhole, the exposure should be 5 stops more. Question 2 I've made a 250 sheet photo paper box pinhole camera with a .013 hole. I'm not getting nearly as much light around the edges as in the middle. I thought it might be the pinhole, so I made another with the same problem. Is lack of light on the edges normal? Yes it is (as explained by erick...@hickorytech.net). The wider the angle of view of your camera the more pronounced that fall off will be, even if you make the hole bigger. Something else that contributes to make it worst is a not so clean pinhole and a pinhole made on a very thick material. Guillermo
Re: [pinhole-discussion] Pinhole mounted in bodycap on EOS cameras
- Original Message - From: Rune Tallaksen tall...@alfanett.no How do I measure the distance from the filmplane til the pinhole? Here is what I did to measure the same in my Nikon camera, before I got hold of the Nikon specs: Make a hole 1/2 or so in the center of your bodycao, mount that bodycap on the camera'd body, set the camera for the maximum exposure time it allows (30 secs in my case), press the shutter, take a cotton swab and insert it thru the bodycap hole until it touches the film plane, make a mark on the cotton swab at the height where the pinhole would be installed, remove cotton swab and measure the distance with a rule. Children, don't try that at home!! Nikon cameras have a distance of 46.5mm from the film plane to the lens flange, Canon EOS have a distance of 44mm. What will the optimal pinholediameter be? It depends which formula you use. anywhere from 0.009 to 0.010 would be fine for an optimum pinhole, if that is what you want. Will my built in exposure be able to measure the light and set a correct exposure? It should, under bright light with relatively fast film. It really depend on the EV sensitivity of the EOS meter system. What else should I think of? Stop thinking, do it and try it, it works!! Guillermo
[pinhole-discussion] Sad note
In case someone here did not know: World-renowned wilderness photographer and writer Galen Rowell, and his wife and business partner Barbara Cushman Rowell, a photographer and writer in her own right, died early Sunday morning in an airplane crash outside of Bishop, Calif. http://www.mountainlight.com/ Guillermo
Re: [pinhole-discussion] Strange Problem and I need some help.
- Original Message - From: Eric S. Theise mat...@cyberwerks.com And the source online that talks about using silver foil and blackening that with selenium toner always seemed very elegant to me. That's Larry Bullis, if memory serves me well. I tried to find a local place that'd roll some silver for me but couldn't find one. That method works well 'cause the toner blacken the silver at a molecular level, so no clogging on the hole can occur, pretty elegant, as you said. Guillermo
Re: [pinhole-discussion] stereo pinhole
- Original Message - From: Bre Pettis pett...@yahoo.com To: Pinhole-Discussion@p at ??? Sent: Tuesday, August 13, 2002 4:05 AM Subject: [pinhole-discussion] stereo pinhole Hi, I'm Bre Pettis out of Seattle and I've become completely obsessed with pinhole photography. I'm just writing in because I'm proud of making a neat pinhole stereo camera. Thta sounds interesting, when can we see some examples? do you have a web page? Guillermo
Re: [pinhole-discussion] 5x4 too small to contact print?
- Original Message - From: gleh...@mac.com I'm currently making pinhole pictures on 5x4 film, with a Leonardo camera. At the moment I scan the negs and print digitally, but for a bit of a change I'm thinking about contact printing them on Printing out paper of some kind, maybe start with cyanotype. I'd be grateful for feedback on what people think about this, too small? or just intimate. 4x5 are just too intimate, IMO :-) I did just that for a while before I bougth a 4x5 enlarger, BTW. I find 5x7 to be a much better size for contact printing, just intimate enough. Guillermo
Re: [pinhole-discussion] (OT) Enlarger help?
- Original Message - From: Steve Bell veracity...@earthlink.net I know another off topic post, but it's kind of on topic, right? i mean, enlargers are often times used with pinholed negs! anyway, my question is, can anyone give me some advice regarding enlargers? i'm building a darkroom in my basement. I'm not exactly sure where to begin when it comes to enlargers. i will be enlarging both color and black and white 35mm, 120, and hopefully other medium format negs. can anyone let me know what their favorites are. i am on somewhat of a budget, but i can afford a semi expensive piece of equiptment. My $0.02 worth of advice: - Buy used, which will save you good money. Many people are going digital and selling their conventional stuff pretty cheap. - Buy the next size up, which in your case would be 4x5. Chances are that eventually you'd want to try one size bigger (at least) than you now think you would. - Buy 6 elements lenses, like Rodagon or Componon-S. There's a big difference between results obtained with 4 and 6 elements lenses. Disregard this advice if you'd be enlarging just pinhole stuff. Guillermo
Re: [pinhole-discussion] Newbie Intro. and a few questions
- Original Message - From: Fox, Robert r...@aarp.org Are there any practical reasons to shoot at 4x5 rather than 8x10? 4x5 is more, well, practical: smaller, less costly to operate, easier to carry and you don't have to get a second mortage to buy an enlarger (if you wanted larger than 8x10 prints, and eventually you would), 4x5 enlargers are readily available. Also, you could buy an inexpensive real 4x5 camera and use it for pinhole work, i.e.: grey calumet, super graphic, any of the other graphic press cameras, etc. I suppose it would be easy enough to do both That's right. My first 8x10 was a cardboard box. but I'm wondering about people's preferences for architectural and portrait work. The multi-format Zero2000 looks like a good starter as well given the choice of formats for standard roll film. You can't go wrong with a Zero2000 they are truly functional pieces of art! Welcome to the list. Guillermo
Re: [pinhole-discussion] (OT again)Alt Process list??
- Original Message - From: Steve [Eazy E] Bell veracity...@earthlink.net So here's a question for all of you. I've heard mention of an alternative process list existing, and i'm wondering if anyone might be able to help me find it. Here is how to subscribe: http://www.photography.gr/links/mlists/details-en.htm?list_id=7 Guillermo
Re: [pinhole-discussion] Checking pinhole sizes (again?)
- Original Message - From: John Moore jlmoor...@yahoo.com The pocket comparator (Item No.: L1873D) is $28.50 the reticle insert (Item No.: M1599D) is $12. $50.50 seems like a good deal for an item that can be used for more than just checking pinhole sizes... of course, I can't seem to think of anything else to use it for- but, no matter. Although 7X is a bit too powerful, it could be used as ground glass focuser. It certainly is a good deal, a more or less similar product cost a lot more here: http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=2121 Now, 7X is for my taste a bit on the low power side to measure pinholes, I think I'd prefer something with more power, perhaps like this: http://www.scientificsonline.com/Products/DisplayProduct.cfm?productid=1357 Guillermo
Re: [pinhole-discussion] hello.....
- Original Message - From: Mark Interrante m...@interwalk.com Ok, I've a question. I recently saw Martha Casanave's Lenin photos (http://marthacasanave.com/lenin.html) and I think they are beautiful. She uses a non-optimial pinhole, and I'd like to know if people have any idea how much larger I would need to make a pinhole to achieve this effect? I missed this post, here is a somewhat late suggestion: Eric Renner's book has a set of pinhole images of the same subject (I believe it is the portrait of a nun or a nun looking girl), each image was made with a differente size of pinhole and if memory serves me well the f/stop is shown for each image, if that is so, just take a a look at the different images, select the one that best represent the effect you want and find how mant stops there are between the sharpest one and your selection, That would be the number of stops your pinhole should be larger than the optimum, in order to get a similar effect. i.e.: your selection is f/128 and the sharpest is f/320, that gives you almost 3 stops between 128 and 320 (128, 180, 256, 360), so the pinhole you want should give you an f/stop 3 stops bigger than the optimum. The above is just a good starting point as there are some othe factors to take into account. A more hands-on approach would be to make a series of pinholes giving 1 stop, 2 , 3, 4, 5 stops and so on, larger than the optimum. That is easily achieved by multiplying the optimum diameter by the f/stop sequence starting with 1.4 so the sequence goes 1.4 - 2 - 2.8 - 4 - 5.6 - 8 - etc., then make exposures of the same scene, using all of the pinholes, develop the film, print the images to the size you'd normally be enlarging the negatives and then select which one is the ONE for you. After the test you should know how many stops larger should the pinhole be, that info could be applicable for other pinhole focal length. An example would be: Camera = your SLR Focal length = 50mm optimal pinhole = 0.010 series of pinholes: (0.010 x 1.4) = 0.014 (1 stop larger that optimum) (0.010 x 2 ) = 0.020 (2 stops larger) (0.010 x 2.8 ) = 0.028 ( 3 stops larger) (0.010 x 4 ) = 0.040 (4 stops larger) Anyway, you get the idea. Guillermo
Re: [pinhole-discussion] Camera Size?
- Original Message - From: ROBERTSON,TRAVIS J is-...@womans.com Thanks for your reply. I am learning about the science of pinhole cameras and I must tell you my head hurts at times trying to figure it out. Stop hurting yourself!!, we really don't need to figure out any science, that was done by Lord Rayleigh back in the late 18 hundreds. Take any calculator (the one provided free by Mr.Gates is fine) and any of the formulas widely available in many pinhole sites (www.??? is a good starting point) and you are set. As far as the result, look at this web site. http://marthacasanave.com/lenin.html . I really like the dreamlike quality of these photos but I would like to have the images a little sharper. Shooting 16x20 is maybe not the best way to get dreamy images. You'd be better off shooting smaller formats and enlarging the results. You should experiment with different pinhole sizes until you get the desired effect. Another way to get dreamy picture is by using Zoneplate lenses (pinhole cousings), mines are not that dreamy but may give you an idea, check http://members.rogers.com/penate/ZP120.html and http://members.rogers.com/penate/ZP120_2.html What I can not figure out is how they did this. See how even the light is. With my oatmeal pinhole camera, more light is located in the center to the photo and gradually gets darker on the sides. Your pinholes probably are not that clean (burrs around its edge) and maybe made using somewhat thick material. Oatmeal cameras should have less progressive fall off compared to flat film plane cameras. One way to prevent fall off, other than using clean pinholes made using thin material is to make cameras with focal length distance equal or larger than the diagonal of the format. If you don't remember what Pythagoras Theorem is about, just take a rule and measure the distance between the corners of your format, the focal length of your camera should have that distance or above. Today, I'm going to find something that will measure the pinhole size. I have been cutting up a coke can and poking the hole in it. I then sand the back down to try and make a clean hole. I suggest you cut the piece of the can, sand it to remove the plasticky coating , then do a poking and at the same time drilling action, sand the back and then gently insert the tip of the needle and rotate it several turns, this just to clean the hole, sand it again only this type use a pencil eraser and then do the rotating action with the needle again, finally, a burst of canned air at both sides. Guillermo
Re: [pinhole-discussion] Camera Size?
- Original Message - From: ROBERTSON,TRAVIS J is-...@womans.com I would like to make 16X20 prints (That is I want to put the paper in the camera) and I'm trying to figure out how large of a pinhole camera I would need. Any suggestions on how to figure this out? Travis, Asking how large a pinhole camera I'd need for 16x20 format is in essence not different than asking: I have an SLR what lens should I buy?. The answer is: it depends on the application and/or results you want to achieve. Having said that, if I was making a 16x20 camera, I'd make it wide angle, perhaps something equivalent to 75mm to 90mm in 4x5 format (in case you are familiar with this format), in other words, I'd make it so it has anywhere from 300mm to 360mm in focal length or distance pinhole to film/paper. You were not asking for pinhole sizes but: As for getting scientific about pinhole, as Chris was refering to, I don't like optimum pinholes either, but I do measure the pinholes I make, I'd hate to poke a hole in a metal foil and by chance get the perfect optimum hole for my camera. By knowing what the perfect optimum hole is and by measuring my pinholes, I can not only know the f/stop of my camera but equally important I can make sure I avoid using the perfect optimum pinhole!! Guillermo
Re: [pinhole-discussion] Reciprocity
- Original Message - From: James Noel jim.n...@gcccd.net What a complicated answer. Simply put, most film is designed to react to light in a linear fashion from about 1/2 second to 1/1000 second. Thanks James, I knew somebody would have a way to explain it in an easier way than me, even if technically speaking that explanation is not quite right, but nevertheless it suits the purpose. Guillermo
Re: [pinhole-discussion] nail hole camera
- Original Message - From: bendur...@aol.com My names Ben I have been a member of the discussion group for a few weeks, but have never posted anything, I just wondered, what is the diameter of the 20 foot tube. Also I dont understand what reciprocity is. Cheers Ben Ben, phographically speaking, EXPOSURE is given by a pair of exposure values, they are TIME and APERTURE and they have a RECIPROCAL relation between them given the same EXPOSURE, in other words, if you increase one value by one stop and reduce the other one by one stop, the EXPOSURE does not change. That is why if your meter tells you need f/8 and 1/8 secs, you could opt to use f/11 and 1/4 secs or f/16 and 1/2 secs, this reciprocity tho fails when the exposure time is (geneally speaking) 1 sec or greater or 1/1000 secs or smaller, some films fail later than others. For instance, if f/16 and 1/2 sec is the indicated exposure, the reciprocity law tell us f/22 and 1 sec is its equivalent, unfortunatelly, for a film like TRI-X, failure kicks in at 1 sec and according to Kodak we should give 2 secs instead of just 1, so for TRI-X for an indicated exposure of f/22 and 1 sec, the reciprocity failure corrected exposure would be f/22 and 2 secs. Now, reciprocity failure doesn't fail arithmetically, otherwise for TRI-X it would be just a matter of doubling the indicated exposure time. Reciprocity fails geometrically, the larger the indicated exposure time the larger the failure. Here is a graphic showing the reciprocity corrections needed for TRI-X: http://www.kodak.com/global/en/professional/support/techPubs/f9/f002_0062gc.gif If the above does not help you, just read some of these sites: http://www.google.ca/search?q=reciprocity+photographyhl=enie=UTF-8oe=UTF-8 Guillermo
Re: [pinhole-discussion] I have a question.
- Original Message - From: ROBERTSON,TRAVIS J is-...@womans.com I have a passion for photography, but the cost of large format cameras and enlargers prevent me from doing the work I want to. Today I found your web site and I have that excited feeling about pinhole photography. You see I want to create very large photos, but I have a question. Can you create a very large pinhole camera and just use photo-paper instead of film? How large is large for you, Travis? Would this one http://shorterlink.com/?W9BIMF be large enough? The answer is yes, you can make them as large as you can get film or paper for. Guillermo
Re: [pinhole-discussion] pinhole and strobe?
- Original Message - From: Margaret Crowe winr...@hotmail.com Hi all, I hope I'm posting this in the right place!! Just wondering if anyone can explain to me why it's not possible to take photos with my pinhole using flashes (strobe)? MARGARET I am afraid that can't be explained, as it is perfectly possible to make exposures (pinhole) using flash/strobes. Guillermo
Re: [pinhole-discussion] pinhole size
- Original Message - From: Jean Hanson jhan...@pon.net I have the math on how to figure the ideal size of the pinholes but how do you actually measure them. Does everyone but me have a microscope, a micrometer? what? Jean Risking being redundant with some of the many good suggestions you have received so far, I'd like to point you to a small article I wrote on that topic: http://members.rogers.com/penate/diameter.htm Guillermo
Re: [pinhole-discussion] HP5, Delta films and reciprocity
- Original Message - From: Shannon Stoney shannonsto...@earthlink.net What do you call this sort of shareware and how would you find it on the internet? A search with the argument best curve fit shareware or just curve fit would do it. In the past I have used one called wincurvefit. If you want to do some reading, go to www.curvefit.com Guillermo
Re: [pinhole-discussion] pinholes and film speed
- Original Message - From: Shannon Stoney shannonsto...@earthlink.net So, I guess it doesn't really matter WHY this is so, as long as I can figure out HOW to make a negative that works for me. That's correct! My intention was not to over analize the WHY but to just point to you there are so many variables involved an a minor deviation from all or several of them can easily account for the seeminly illogical at simple inspection result (to me at least). Guillermo
Re: [pinhole-discussion] pinholes and film speed
Shannon, Numerically, an EI of 1000 may seem as a big jump from ISO-400, but it is really just 1 1/3 stops faster, which probably can be accounted by a combination of factors like: how thin you want the negatives low zones to be, a bit of anomalies in the reciprocity correction (I am not saying your method is incorrect) and the pinhole actual diameter being a bit bigger than what you think it is. Beside the above, 400 is the ISO speed of HP5 when processed as per the ISO standards, but it could prove to be a bit faster with your specific processing. An small contribution from all or several of the mentioned factors could easily make your 400 film appear to be 1000 film, instead. Guillermo - Original Message - From: Shannon Stoney shannonsto...@earthlink.net I have been testing with HP5+ film to see what film speed to shoot it at. To my surprise, it seems as if its speed in my pinhole camera is about 1000! It's rated at 400. The way I figure exposures is based on the fact that my pinhole is f352. That's supposed to be 30 times whatever f64 is. So I multiply the f64 time by 30 and then adjust for reciprocity failure, using a formula I found online from Ilford: raise the metered time to the 1.48 power. This accords with most reciprocity failure charts that I've seen. But to get my shadows thin enough, I have to shoot this at 1000. I have had a lot of old cameras with old shutters that required different speeds than the regular one because, I assume, the shutter is a bit slow. But a pinhole doesn't have a shutter really! So, I wonder why you end up having to shoot as if the film is much faster than it is? Has anybody else noticed this? /
Re: [pinhole-discussion] 126 pinhole camera
- Original Message - From: ROGER ARMOUR ro...@rharmour.fsnet.co.uk I am still using this camera ( camera box made from black card and attached to a cartridge of 126 film - increasingly difficult to get hold of! The pinhole is made from aluminium pastry foil) despite manual wind-on problems etc. Could Guillermo or one of the experts please tell me who first described it. Do you have the reference to a paper or did it first appear on the internet? I'm hoping to write a paper and would like to give credit to the person. Thanks, and happy pinholing everyone Roger, as far as I know, it was Kodak who first described it, there are several sites having a copy of the document, PV site has it too, here is a link to it: http://www.???/resources/pinhole126/pinhole.htm Guillermo
Re: [pinhole-discussion] increased sharpness?
- Original Message - From: Jim Kosinski mer...@paintcancamera.com it makes any difference... does anyone know the range of wavelengths that bw paper is sensitive to? Both Ilford and Kodak have spectral sensitivity curves for their papers in their respective sites. Guillermo
Re: [pinhole-discussion] used enlargers
- Original Message - From: Eric S. Theise mat...@cyberwerks.com Are there any 4 x 5 enlargers that will handle the full negative or do I need to go to a larger size? Yes, a 5x7 would do what you want. A cheap option, if you can find one, is an old 5x7 Elwood Guillermo
Fw: [pinhole-discussion] focal plane shutter theory
I was reading my own post and noticed a mistake when converting inches to millimeters. I used a factor of 24.5 when in fact an inch is equal to 25.4 millimeters. The time to move across I talked about, therefore, should be: Time to move across film: (5 x 25.4) / 120 = 1.058333 seconds Not a big difference, but if NASA failed a mission to Mars because a conversion error, I don't want you to miss your exposure due to my conversion mistake :-) Guillermo Let me think in written voice here: Since the film will be stationary, if we draw a very thin line on the film (parallel to the shutter's slit), when the slit is moving accross the film it will see that thin line passing by, the amount of time it takes that line to go from one end of the slit to the other will be the exposure time. Exposure time, therefore should be given by: Exposure time = slit width / speed of shutter moving across the film for instance: If you want an exposure time of 1/60 seconds and you have a slit 2mm wide, you FP shutter should move this fast accross the film: FP shutter speed = Slit width / Exposure time FP shutter speed = 2 / (1/60) = 120 mm/second If the film is 4x5 (landscape), the FP shutter should take this long to move accross the 5 length of the film: Time to move accross film: (5 x 24.5) / 120 = 1.0208333 seconds Thinking over !! Guillermo
Re: [pinhole-discussion] focal plane shutter theory
- Original Message - From: Uptown Gallery mur...@uptowngallery.org This may be off topic, but the breadth of knowledge within this group may provide me an answer (off list , if necessary). I would like to understand (actually, analyze) the operation of a focal plane shutter, for the purpose of building one for sheet film. I want to get a grasp on calculating exposure duration as a function of slit width and linear speed, I guess (or direction to what I should be thinking about). Let me thin in written voice here: Since the film will be stationary, if we draw a very thin line on the film (parallel to the shutter's slit), when the slit is moving accross the film it will see that thin line passing by, the amount of time it takes that line to go from one end of the slit to the other will be the exposure time. Exposure time, therefore should be given by: Exposure time = slit width / speed of shutter moving across the film for instance: If you want an exposure time of 1/60 seconds and you have a slit 2mm wide, you FP shutter should move this fast accross the film: FP shutter speed = Slit width / Exposure time FP shutter speed = 2 / (1/60) = 120 mm/second If the film is 4x5 (landscape), the FP shutter should take this long to move accross the 5 length of the film: Time to move accross film: (5 x 24.5) / 120 = 1.0208333 seconds Thinking over !! Guillermo
Re: [pinhole-discussion] speed of paper versus film
- Original Message - From: lwilkin...@schilli.com I'm struggling to understand the relationship between film and photographic paper. Specifically, calculating exposures, etc. Where film may be considered ASA 100, paper may be considered P100. Obviously, it's not the same 100...but what's the relationship? Papers have 2 ISO parameters associated with them, ISO R and ISO P. The former has to do with the density range a paper or combination paper+filter is capable of. The latter is the speed of the paper. Ilford MGIV, for instance, has a speed of ISO P500 when unfiltered. As for the relationship, take the 500 divide it by 100 and you will get a rough estimate of the paper's speed when used as FILM. Using that relationship we find that MGIV has a film speed of ISO-5. If you do a search of this list messages, you'll find that ISO-6 is a very common used value, ISO-5 or 6, close enough, IMO. If you use, let's say, a #0 filter, the ISO P speed becomes ISO P200, so your paper will behave, approximately, as film ISO-2 (I'd approximate that to ISO-3, BTW). Once you know the film speed of your paper and if you know the f/stop of your pinhole camera, calculating exposure is business as usual, with the exception of reciprocity, for which here is a table in a little article I wrote some time ago: http://members.rogers.com/penate/pinsize.htm Hope it helps, Guillermo
Re: [pinhole-discussion] pinhole is not about sharpness?
- Original Message - From: michael_georg...@trendmicro.com Pinhole can be about sharpness, as well as softness... it's also about time, and light, perspective, art, science, chance and fun! In the very far past I've been nailed in this list because of my interest on the scientific and mathematical approach to it, which has included the use of the so called OPTIMUM formula that is supposed to give us maximum sharpness, and the measuring of pinholes using microscopes. Now, you are nailing me because a statement I made was perceived as meaning I reject (for lack of a more suitable word) sharpness.Common, cut me some slack, will ya Michael !! :-) No pinhole image will ever be sharp, in the lens photography sense of the word. In that respect, the reason we practice pinhole obeys to higher causes, higher than sharpness. Your reasons may or may not be the same as my reasons and even if they were the same, their order of importance could be different between yours and mine. Now, the above does not limit some of us (yes, I am one of those, believe it or not!) to want to get as sharp pinhole images as we can get, either sometimes or all the time. Science has never failed me, hence my advice to use the scientific formulation as the point from which deviate (or not!). Guillermo
Re: [pinhole-discussion] Optimal pinhole size question - theoretical practical
- Original Message - From: Tom Harvey harv...@aracnet.com It's the very, very that I wonder about. I believe that Zernike Au has said that he used the smaller aperture because tested out sharper. Aside from lengthening exposure times, would using small size pinholes on cameras with focal lengths of twice the optimal focal length be any less sharp? Tom, All optimum pinhole formulas, starting with Lord Rayleigh's (1891) to the most modern one, like the one in M.Young's article foound at PV site, can be expressed as: Diameter = SQRT( K * F * Lambda ) That constant K has taken many values, some based on analitical reasons, some based on experimental reasons. You implicitly mentioned 2 values, the one in Renner's book, which BTW is congruent with modern formulations and Zernike's, which you mention to have read was found experimentally and gives way smaller diameters than the modern scientific formulation. I know of another experimental value, that found by C.Patton, which oddly enough, gives larger diameters. So there you have it, science says something and 2 pinholers have found experimentally that a larger hole produces better resolution (Patton) and the other (Zernike) than a smaller hole produces better results. I have to mention that Patton's value doesn't deviate drastically away from the scientific formulation as Zernike's does. Since pinhole is not about sharpness, use any pinhole size for a particular distance pinhole-film, but I suggest you use what I call the scientific formulation as the starting point from which deviate. Guillermo
Re: [pinhole-discussion] Film transport system for 120 film
- Original Message - From: Maria Grant mgran...@san.rr.com Were can I buy a film transport system for 120 film? I hope I'm using the correct terminology. I've seen cameras made from coffee and tea containers with film transports,but can't seem to find this item,would I have to find a old 120 camera and use its system? Can I us the transport from a cheap plastic camera? Thanks in advance. I know which coffee/tea cameras you mean, I think the guy is Italian, BTW. I emailed him some time ago and he said, very politely I must say, he doesn't sell film winding mechanisms or ready made cameras. I think you could adapt the mechanisms you mention, it'll be a matter of finding the right coffee/tea container for it, but it should be doable. Guillermo
Re: [pinhole-discussion] Not on Subject
- Original Message - From: James Kellar pinh...@jameskellar.com I know this is not on the subject of pinhole or even photography, but I just couldn't help myself. Goto http://207.67.219.101/objective/propaganda.html, and then scroll down to Apple Macintosh: This is kind of funny and scary all at the same time. I knew I shouldn't buy a Mac, now I know why. Many thanks for the link James. Guillermo :-)
Re: [pinhole-discussion] Ultraviolet Light Pinhole Camera Project
- Original Message - From: Adam Leiferman leiferm...@kimball.k12.sd.us First I shone the UV laser on a front-surface convex mirror. I then made pinhole lenses specifically constructed to create the best images for the wavelength of light that I was using. The pinhole's size was found through a formula that is available at the site http://www.???/resources/articles/Young/. The photograph taken with UV light was slightly sharper and clearer than the photographs taken with red light. The reason is that the small wavelength of the UV light causes less image blurring due to diffraction. To be sure that the formula I used for the pinhole size was correct, I then made pinhole lenses that were slightly smaller and slightly larger than the optimal size predicted by theory. I took pictures with each and the results agreed with the equations. The smaller-than-optimal pinhole caused the photo to be slightly diffracted and the larger-than-optimal pinhole caused the photo to be a little blurrier due to the increased hole size. Adam, Many thanks for lettings us know of your tests. There is a number of us interested not only in the aesthetics of pinhole photography but also in the science behind it. These kind of things are interesting and exciting for us (for me, anyway). The article you mentioned above, from which you took the formula for optimum pinhole size gives a formula and a approximated one, the latter being: S^2=lambda*F and the former: S^2=0.61*lambda*F. You took images using smaller-than and larger-than the optimum size, my question is: which formula did you use to find your optimum size? Thanks again, Guillermo
Re: [pinhole-discussion] darkrooms in Toronto
Liav, Check the darkrooms at Gallery44 in downtown Toronto, here is their URL: http://www.gallery44.org Guillermo - Original Message - From: Liav Koren yu257...@yorku.ca To: pinhole-discussion@p at ??? Sent: Friday, April 19, 2002 6:01 PM Subject: [pinhole-discussion] darkrooms in Toronto This isn't really a pinhole question; sorry. I'm looking around for a darkroom to work in over the summer, until school starts again. Does anyone have any recommendations for commercial darkrooms in Toronto (ie, a place where I can go in and print, not a place that will print for me). I'm in North York, but anywhere accessible from TTC is good.
Re: [pinhole-discussion] best viewfinders for close-up work
- Original Message - From: Sarah Heidt heidtsa...@hotmail.com My younger brother does woodworking and has generously offered to build me a large format pinhole camera. He even bought a set of micro drills for his Dremel (are these small enough, I don't know!) Nothing like the love of a brother! As for the micro drills, they come in wire gage sizes, here is a table: http://www.labenson.com/jobbers%20drills%20hss%20wire The Decimal Dia is the diameter in inches, you need that to calculate the focal length (distance pinhole to film) the holes made by the drills are optimum for. To find the focal length, just divide the drill diameter by 0.0073 and multiply the result by itself, that will give you the focal length in inches. I have seen specs for microdrill bits of up to #97 wire gage size, the table above only has up to #80, which is good for about 90mm focal length, a good focal length for a very wide angle 8x10 camera, I'd say. All I have to do is give him the plans. (Don't give me grief about not building it for myself--I'm a busy mom of two little girls, and shy of power tools...) Oh, the joys of parenthood! I am not sure whether to go 4x5 or 8x10. I don't have film holders. So should I purchase a wooden film holder first on Ebay and then have him build the camera to accomodate it? If you don't have a 4x5 enlarger (bro could build one too I guess :-) I'd recommend to go with an 8x10, you can contact print the negatives and have a nice size result. Yes, buy the holder first, it'll help your brother. I have the book Primitive Photography by Alan Greene that shows very detailed plans for making a large format camera (with lens!) and I was thinking of giving the book to him and letting him use that as a guide. Any other ideas or plans that are online I could send to him? Give him the book, tell him the most important part of the camera is the back. Show him also Bender's pinhole page, so he gets some additional ideas. Here is the site: http://www.benderphoto.com/pincam.htm Here is an excellent view of a good back design: http://www.enteric.org/810/images/17.jpg Hope it helps, Guillermo
Re: [pinhole-discussion] Film Development
- Original Message - From: Richard Heather rheat...@slonet.org neither of us are right. 24x36x36 =31,104mm2 8(x2.5)x 10(2.5) = 50,000 mm2 Richard Heather Richard, Remember that the actual length of film allows for 36 frames + leading and trailing portions of film (probably the equivalent to 5 to 6 extra frames). In addition, the width of the film is not 24mm but 35mm and there are 2mm separating each frame, also. All that, minus the area for the sprocket holes. So w/o accounting for the trailing and leading portions of film and the sprocket holes, the area would be: 35 x 38 x 36 = 47,880 mm2 Guillermo
Re: [pinhole-discussion] my first photo
- Original Message - From: Matti Koskinen mjkos...@koti.soon.fi I have Corel PhotoPaint) I use only Linux and Gimp, win98 crashes almost every time I try to scan. You're doing the plugging but not the praying, obviously. Remember W98 is plug and PRAY! I placed a #0 filter behind my camera and took photos. They're still drying, but looks like they are really much better with tonality than without the filter. Filter kit I have is Ilford Multigrade. The tests I made showed that in a clear sunshine without filter 30 sec. was enough but using filter 2 mins. had to be exposed. Any reason for this long exposure? The guide in the filter box says that when enlargening using #0 filter has no effect in exposure time. 2 reasons: -Those filters are made to filter tungsten light and you are using them to filter daylight. That may account for the increased time. -Since the use of the filter increases the uncorrected exposure time, reciprocity corrections become a bit drastic and increases the reciprocity corrected time even more. My camera is 4x5 from an article of Popular Woodwork, searching the web gave this link, but I printed the article so I don't have the url anymore. Focal length is 120 mm. Here is the link: http://www.popularwoodworking.com/features/fea.asp?id=1048 Guillermo
Re: [pinhole-discussion] Developing 8x10 sheet film
- Original Message - From: Greg Newberry grnewbe...@qwest.net Well, I've been going along happy as a clam designing my 8x10 pinhole camera when all of a sudden I realized that if I shoot sheet film, I'm going to have to develop it! So I know you can do it in a tray, and I've seen the sheet film holders that stand up vertically in a box of developer, but what is the best way? It seems that agitation may be an issue in a tray, but a box full of developer and the vertical film holders would use a lot of developer, plus you would need three. Then washing them? Is this the current best technique? I develop 8x10 in trays, but you could use a simple hybrid technique of trays+drum. Buy a piece of ABS 4 diameter pipe, film goes inside pipe and then pipe in the tray. Agitation is achieved by rotating/rolling the pipe. You could also buy one of those 8x10 print drums, they are constantly listed at eBay, with or w/o motor base. Guillermo
Re: [pinhole-discussion] paper negative tricks
- Original Message - From: Andy Schmitt aschm...@warwick.net or build a developing tube or 2..then you just load roll...sort of.. 8o) andy That's another possibility. Here is a link to a design I have read is effective: http://people.smu.edu/rmonagha/brontube.html Guillermo
Re: [pinhole-discussion] paper negative tricks
You are in Suomi, isn't that right Matti? I visited Turku (University of Turku) and Helsinki, way back in the spring of 1978, Finish people were very friendly and kind to us every where we went and stayed. Anyway, there are daylight tanks that allow you to process 4x5 film without a darkroom, all you need is a changing bag to load the film in the tank. I use a COMBI PLAN 4x5 TANK ( http://www.hpmarketingcorp.com/hp_combi.html ), it is made in Sverige, so I'd imaging stores in Helsinki or in Stockholm, carry it. There are other tanks like the Yanki and couple of Jobo ones, but I haven't use them, myself. Guillermo - Original Message - From: Matti Koskinen mjkos...@koti.soon.fi yes, film would be an ideal solution, but to develop it is the problem. It's fairly easy to develop a paper negative in my minimal darkroom (a closet which is the only place I can darken totally) but to develop a film, as the only way would be to develop sheet film is in trays, and I think that would just be a mess. First thing would be to put the film first in the stop bath or fixer. But having a safelight makes things little bit easier. Litho film is one thing I'm going to give a try, but it's also high-contrast. And pinhole day is coming soon...
Re: [pinhole-discussion] paper negative tricks
- Original Message - From: Matti Koskinen mjkos...@koti.soon.fi I finally got my wooden 4x5 camera lightproof and taken few test shots using paper negatives. Problem with paper negative seems to be the total lack of details in the sky, getting the sky with some clouds make the print look more real. One way is to use film instead of paper and also use a red filter. Guillermo
Re: [pinhole-discussion] Brand New Pinhole User Questions
- Original Message - From: Katharine Thayer ktha...@pacifier.com Just remember, if you're using an 8x10 filmholder, that 8x10 paper is bigger than 8x10 film, and you'll need to shave a little off each side of the paper to make it slide into the holder smoothly. Katharine Thayer Try it before you shave, my 8x10 holders take 8x10 paper sans shaving.
Re: [pinhole-discussion] human subjects
- Original Message - From: Joe Rollins jroll...@starband.net GlacierI am trying to build a pinhole camera to use to take photos of human subjects. I need to get the time down to under 10 or 15 seconds. I shoot with Ilford MGIV. What focal length and diameter pinhole would be sugested. Joe Rollins I am sorry to say, that this is a case for which a little bit of math comes in handy. As Thom said, you don't give too many details of your shooting, so I am going to make some assumptions. I am going to assume you want to use an optimum size of pinhole and that you will be shooting with a light level equivalent to f/16 @ 1/6 secs, that BTW is the indicated exposure for shooting outdoors under open skies/bright sunny day, otherwise known as sunny16 rule. I am also assuming you rate MGIV as ISO-6. Here is the analysis: As per reciprocity table for MGIV (see it in my paper Determining Pinhole Size and Exposure at http://members.rogers.com/penate/pinsize.htm ), for a 10 to 15 secs max exposure time you would need an uncorrected time of no greater than 8 secs. If existing light level calls for an exposure of f/16 @ 1/6 secs, we need to find an equivalent pair of exposure values for when the exposure time is 8 secs. The answer is f/128 @ 8 secs. Once you know the f/stop your pinhole camera must have, which is f/128, you can find the focal length for which when using an optimal pinhole size, you'd get an f/stop of f/128, you do that with this formula: Focal length in millimeters = (f/stop x f/stop) / 738 In your case, f/stop = f/128, so we have: Focal length in millimeters = ( 128 x 128 ) / 738 Focal length in millimeters = 16384 / 738 Focal length in millimeters = 22 mm Further explanations upon request. Guillermo
Re: [pinhole-discussion] Re: image circle relative to focal length/fstop
- Original Message - From: Zernike Au zern...@zeroimage.com If you want to control the circular image to 2' or 3 (the range is quite big!), the main factor is the thickness of the front panel of your camera that hold the pinhole and where you mount the pinhole, and also the size of the opening of the front panel. Sure, that's a way to restrict the size of the image circle. If you go that way, instead you may just want to make a circular cut out of opaque material, print the image with your enlarger then place this circular cut out in the center turn on the room lights some seconds, presto! you have your circular image! Photoshop would make it even easier/faster to achieve it. Not quite sure the aesthetics would be what Thom is looking for, tho, but as always, I may be wrong. Guillermo
Re: [pinhole-discussion] Ideas for finishing pinhole
Jeff, You could probably find Aluminum oxide at a science store or if there is one in your location, at a lapidary supplier. You could also use the rubbing paste auto painters use to polish cars after they have been painted. A better idea would probably be to thin the material by hammering with a ball hammer against a solid metal surface, like blacksmiths do. Aluminum is soft so there is no need for heating it, I believe. A better material than the brittle alu.pie is the aluminum of a pop can, sand the non printed side (first or last) as it has a plastic like coating. And finally, if you don't want to be thinning material, you could go to a automobile parts store and buy BRASS SHIM STOCK, they sell it in different thickness, you may want 0.001, 0.002 or 0.003, these guys call it 1 thou, 2 thou and 3 thou (thou as in thousand). 0.002 is generally the best thickness, IMO. not too thick that causes fast fall off, not too thin that is difficult to work with. Guillermo - Original Message - From: Jeff jrodg...@elite.net To: pinhole-discussion@p at ??? Sent: Tuesday, March 26, 2002 1:12 AM Subject: [pinhole-discussion] Ideas for finishing pinhole Hello, made my first pinhole from aluminum pie tin, but I need to thin the material some more. Sanded with 600 wet/dry paper, but have a better idea: using fine grit and a marble, a concave surface could be formed... hopefully at it's thinnest near the pinhole. Anyone tried similar method? I'm trying to find a source for the grit (like is used to grind glass) and hopefully don't have to mail order. Any suggestions for where to find this stuff locally?
Re: [pinhole-discussion] image circle relative to focal length/fstop
- Original Message - From: Thom Mitchell tjmi...@ix.netcom.com Would then a thick material create a smaller circle with the same image quality (or not) as a thinner material? These may be simple questions but I want to be able to control the size of my image circle, either through pinhole size or focal length. It now sounds like material thickness could be a 3rd variable to play with, and possibly the most productive. Any other advice out there? Thanks for the responses so far. Thom The 2 variables you have are distance pinhole to film/paper and thickness of the pinhole material. The distance or focal length will cause a slow light fall off, as given by an esoteric physical/optical law, sort of. A pinhole made on a thick material would cause a very fast, almost sudden fall off, due to vignetting (have the impression this is what you're looking for, but I may be wrong). As far as specific examples, calculation would have to be made to find them out or to find possible rules of thumb, but since the requirement is no math, trial and errors would have to be made to find a possible relation between thickness of material and fall-off. The relation between focal length and fall-off was already answered by Tom in a previous message. There is a 3rd variable and is the ratio pinhole diameter versus thickness of material, but let's not go there 'cause it would complicate and augment the empirical tests. Guillermo
Re: [pinhole-discussion] Slightly Off Topic
- Original Message - From: Jim Kosinski mer...@paintcancamera.com http://directory.google.com/Top/Science/Astronomy/Amateur/Astr ophotography_and_CCD_Imaging/ Jim K Jim, your link broke down, this happens to me all the time. I have found this site in which you paste a long link and it will generate a short one that will automatically sent you to the long one, I find it very useful. The site is http://makeashorterlink.com/ For instance, the above link you gave, becomes this very short one: http://makeashorterlink.com/?T1102059 Just an FYI. Guillermo
Re: [pinhole-discussion] Epson Perfection 1250 Photo Flatbed Scanner
- Original Message - From: Derek Clarke dere...@cix.co.uk TBH these dual-use flatbeds are still better for opaque material than transparency use, especially 35mm. So they are still inferior to a true film scanner at the same scan resolution. Also the transparency illuminator is usually limited to 5x4. If what you say is true, they could even improve the results of a too sharp pinhole. :)) Guillermo
Re: [pinhole-discussion] RESOLUTION AND PINHOLE
- Original Message - From: Philippe Monnoyer monno...@imec.be I still have to read the interesting paper. So if my optimal pinhole diameter for a 100 mm FL is 0.36 mm, this means that my 24x30 cm film will record an image where every point will have a blur of 0.36 mm. So it is impossible to have sharp detail with pinhole photography ? Isn' it ? Yes it is, and there are many samples out there in ciberspace to confirm that. In Renner's book there is 1 image, as a matter of fact, that is as -perhaps- sharp as pinhole can get. When you read the paper, you'll see that you can get a resolution equal to 1.5 times what 0.36 give you. 0.36 give you 2.78 image points per mm, actual resolution would then be 2.78x1.5 or 4 lpmm, which when viewed at a confortable distance of vision (13 or so) should look reasonable sharp (notice the sharp is under quotations mark). Guillermo
Re: [pinhole-discussion] RESOLUTION AND PINHOLE
- Original Message - From: Philippe Monnoyer monno...@imec.be Image point radius = 0.61 * light_wavelength * focal_length / pinhole_radius Indeed, according to that equation, the bigger the pinhole, the smaller the Image point radius and the sharpest the image. Mea culpa! I admit. What I called Image point radius is actually Airy disk radius, which is the radius if the 1st order diffraction ring (I believe that's what is called). The key word here is diffraction, in that respect, is understandable that the bigger the pinhole radius, the smaller the Airy disk's one, in other words, the smaller the diffraction effect. And the smaller the pinhole the greater the Airy disk and the diffraction effect, which is what is happening when you use a 170µm, not for its optimum FL of 21mm or so, but for a FL of 100mm. By the way, I called it Image point radius, so later I could equate that to the image point produced by a large pinhole, which for will not be affected by diffraction (for our purposes) and that will project image points equal to the size of the large pinhole itself. The so called optimum pinhole happens when the curve: Airy disk radius = 0.61 * Lambda * FL / pinhole_radius intersects the straight line: Image point radius = pinhole_radius Therefore: pinhole_radius = 0.61 * Lambda * FL / pinhole_radius or Pinhole_radius = SQRT (0.61 * Lambda * FL / pinhole_radius) or when using Lambda = 0.000555mm Pinhole_diameter = 0.03679 SQRT( FL ) Sorry for the confusion, Guillermo
Re: [pinhole-discussion] Pinhole Calculations
Hello photoian at earthlink.net:
Trying to answer all your questions, after Richard answers would be redundant.
I will though, answer a question Richard did not addressed:
- Original Message -
From: {USER_FIRSTNAME} {USER_LASTNAME} photo...@earthlink.net
The formula is pinhole(in) = square root FL x 0.0073 or pinhole(mm)= square
root FL x 0.03679.
My question is; does this formula really give the sharpest image?
The constant (.oo73 or .03679) is what determines the
answer. So, now the question is; How is the constant determined?
Does it give the sharpest image or is it just a trade off
between exposure time and pinhole size?
The formula is a trade off between geometrical sharpness (the smaller the hole
the sharper the image) and diffraction (the bigger the hole the less the image
sharpness is affected by diffraction).
Science tells us the radius an image point imaged by a small aperture is given
by the formula:
Image point radius = 0.61 * light_wavelength * focal_length / pinhole_radius
A purely geometrical analysis will show us that the image point radius would be
the same size as the pinhole radius:
Image point radius = pinhole radius
So when the 2 formulas above are equal, we have a balanced trade off you talk
about:
pinhole radius = 0.61 * light_wavelength * focal_length / pinhole_radius
therefore:
pinhole_radius^2 = 0.61 * light_wavelength * focal_length
or
pinhole_radius = SQRT (0.61 * light_wavelength * focal_length)
or
Pinhole_diameter = 2 * SQRT (0.61 * light_wavelength * focal_length)
If we select light with wavelength of 0.000555 mm, we would have:
Pinhole_diameter = 2 * SQRT (0.61 * 0.000555 * focal_length)
or
Pinhole_diameter = 0.03679 * SQRT ( focal_length) millimeters
The equivalent in inches is:
Pinhole_diameter = 0.00073 * SQRT (0.61 * light_wavelength * focal_length)
Guillermo
Re: [pinhole-discussion] Zero 6x9 pinhole
- Original Message - From: cfowler cfowl...@tampabay.rr.com I am getting ready to order the zero 6x9 multiformat pinhole camera, has anybody used this camera's ? is it worth 200 Bucks ? I don't own the camera, but I've seen it and -as I have said before, the darn thing is a beauty, no question about it. From the point of view of craftmanship I'd say it is worth the 200 american pesos and I'd bet its pinhole-photographic functionality is up there, too. I have mostly used large format camera's, I have a big 5x7 view camera, I dont think it be hard to convert to pinhole A view camera hardly needs any thing done to it to convert it to pinhole camera, you just basically need to use or dedicate a lens holder to mount a pinhole on it. but how do select the distance of the bellows ( pinhole to film plane ) ? is there certain rule ? You mention the distance pinhole to film plane, that is the focal length of your set up. The rule, (which is meant to be broken to suit your purposes, BTW) is given by the formula for the optimum pinhole diameter. You don't have to use that distance, but at least it gives you a reference point from which depart. If you don't care in measuring pinholes and calculating optimum diameters of focal lengths, then, you don't have to care in measuring the bellows extension, either, just find by trial and error a bellows extension point you like the results from and that would be the optimum focal length for that particular pinhole. Guillermo
Re: [pinhole-discussion] Re: mini-pin + photo flo sub
- Original Message - From: Christian Harkness chris.harkn...@eudoramail.com Well, I once used a liguid detergent for dishwashers instead of Photo-Flo it throughly ruined my negatives, much worse then if I had not used Photo-Flo. so Did you use a lot? You just need a drop on a liter of water.
Re: [pinhole-discussion] Photo-flo
- Original Message - From: Tim Midkiff ku...@vci.net This may be a bit off topic but, is there a readily available subsitute for kodak photo-flo? I happen to be at home today and need to develop some images, both pinhole and otherwise, and i'm being plagued with spots and such. please send and ideas!!! Photo-flo just helps get rid of the water's drops surface tension, it does not have any magical properties, it is basically soap without color or fragrance added to it. If I where you and didn't have photo-flo, I'd use 1 or 4 drops of dawn (i.e.) in a liter of water. Guillermo
Re: [pinhole-discussion] Favorite Cameras?
- Original Message - From: Liav Koren yu257...@yorku.ca This makes me wonder: has anyone else also been working with a converted disposable and 35mm film? It took me a few tries to figure it out, but once I learned to chop the thing in half properly, I got a camera that I'm pretty happy with.. I made this ugly 14mm focal length one many years ago: http://members.rogers.com/penate/cameras/14f.jpg http://members.rogers.com/penate/cameras/14r.jpg http://members.rogers.com/penate/cameras/14b.jpg But I have discontinued its use in favor of this -non disposable- one: http://members.rogers.com/penate/cameras/12.jpg Guillermo
Re: [pinhole-discussion] countdown timer
- Original Message - From: Gordon J. Holtslander hol...@duke.usask.ca Its called a parking timer. Its a keychain with a clock and countdown timer. You can set it to time a certain interval of time. when the time has expired it will beep. Cost $6.00 Canadian (thats $0.25 US) Great for timing pinhole exposures or even processing time when doing sheet film in the dark. Great! I have 8 bucks in Canadian Tire money (that's about $0.34 US :-) burning my pocket that I could use to pay for that timer. You have the ITEM# handy by any chance, Gordon? Guillermo
Re: [pinhole-discussion] reciprocity and TMY film
Allow me just 1 more try, pls: corrected time | (100,300) P | _ |_ | _ | _ | _ | _ | _ | _ | _ | _ |_ | _ | _ | _ P --- (10,15) |_P ^ indicated time |
Re: [pinhole-discussion] reciprocity and TMY film
Told you they were axis of evil, can't get the chart to format correctly, here is the last try: corrected time | (100,300) P | _ | _ | _ | _ |_ |_ | _ | _ | _ | _ | _ | _ |_ | _ P --- (10,15) |_P ^ indicated time | | (1,1.25)
Re: [pinhole-discussion] reciprocity and TMY film
** Resending the message, hopefully the ascii chart won't break up this time. - Original Message - From: I Zarkov dr_izar...@hotmail.com Unfortunately the Kodak product search engine gives nothing for the topic of 'reciprocity'which is too bad because they once had a very good chart in an old professional products catalogue that gave a good long and short range adjustments for reciprocity [ i.e.: 1-10 sec and 10-100 sec ranges]. I'll see if I can find it somewhere else. Zarkov, TMY film needs relatively weak reciprocity corrections. If you, judiciously, add between 25% and 50% more exposure for indicated times between 1 to 10 secs, and between 50% and 150% between 10 to 100 secs, your exposures should be -enough- well corrected. For non T-Grain films (i.e. Tri-X), you'd need to increase the exposure 1200% for an indicated time of 100 secs. Clearly, the need for better charts is there more for Tri-X than for TMY, for the range 1 to 100secs indicated, at least. I've seen the chart you mentioned, you can still pull it from Kodak's site, here is the URL (cut and paste it if it breaks): http://www.kodak.com/global/en/professional/support/techPubs/f9/f002_0062gc. gif Another issue in the case of TMY and TMX, for that matter, is they (Kodak) only gives us 3 correction values (1, 10, and 100). We need at least 3 points to plot a curve and that is what Kodak gives us (it'd be nice to have at least y more between 10 and 100). Now, by seeing many other reciprocity correction charts for other films, we know that this reciprocity phenomenon is not linear but exponential, so we use that knowledge to plot a curve for TMY based on the 3 points we have [( 1,1.25), (10,15), (100,300 )]: corrected time | (100,300) P | _ | _ | _ | _ | _ |_ |_ | _ | _ | _ | _ | _ | _ |_ | _ P --- (10,15) |_P ^ indicated time | | (1,1.25) Once you have your graph, it is just a matter of drawing vertical lines from the indicated time axis and from where this vertical line intersects the curve, horizontal lines to the corrected time axis to find/read the, reciprocity corrected time. MAKE NO MISTAKE, this 2 axis are photography's AXIS OF EVIL, I am, as we speak, writing my Pres. requesting military action against them! The same treatment can be made to any other film for which you know at least 3 corrections. Guillermo
Re: [pinhole-discussion] reciprocity and TMY film
- Original Message - From: I Zarkov dr_izar...@hotmail.com Unfortunately the Kodak product search engine gives nothing for the topic of 'reciprocity'which is too bad because they once had a very good chart in an old professional products catalogue that gave a good long and short range adjustments for reciprocity [ i.e.: 1-10 sec and 10-100 sec ranges]. I'll see if I can find it somewhere else. Zarkov, TMY film needs relatively weak reciprocity corrections. If you, judiciously, add between 25% and 50% more exposure for indicated times between 1 to 10 secs, and between 50% and 150% between 10 to 100 secs, your exposures should be -enough- well corrected. For non T-Grain films (i.e. Tri-X), you'd need to increase the exposure 1200% for an indicated time of 100 secs. Clearly, the need for better charts is there more for Tri-X than for TMY, for the range 1 to 100secs indicated, at least. I've seem the chart you mentioned, you can still pull it from Kodak's site, here is the URL (cut and paste it if it breaks): http://www.kodak.com/global/en/professional/support/techPubs/f9/f002_0062gc. gif Another issue in the case of TMY and TMX, for that matter, is they (Kodak) only gives us 3 correction values (1, 10, and 100). We need at least 3 points to plot a curve and that is what Kodak gives us (it'd be nice to have at least y more between 10 and 100). Now, by seeing many other reciprocity correction charts for other films, we know that this reciprocity phenomenon is not linear but exponential, so we use that knowledge to plot a curve for TMY based on the 3 points we have [( 1,1.25), (10,15), (100,300 )]: corrected time | P --- (100,300) | _ | _ | _ | _ |_ |_ |_ | _ | _ | _ | _ | _ | _ |_ | _ P --- (10,15) |_P ^ indicated time | | (1,1.25) Once you have your graph, it is just a matter of drawing vertical lines from the indicated time axis and from where this vertical line intersects the curve, horizontal lines to the corrected time axis to find/read the, reciprocity corrected time. Make no mistake, this 2 axis are photography's AXIS OF EVIL, I am, as we speak, writing Pres.Bush requesting military action against them! The same treatment can be made to any other film for which you know at least 3 corrections. Guillermo
Re: [pinhole-discussion] reciprocity and TMY film
Try this values: Indicated,Corrected 10,15 12,21 15,27 20,35 25,47 30,62 40,1:24 50,1:50 60,2:25 80,3:10 100,4:10 Guillermo
Re: [pinhole-discussion] New image saloon uploaded on behalf of Pete Eckert
- Original Message - From: pete eckert peteeck...@mindspring.com Guy, You are right it is a zone plate shot. No doubt Guy, you are a pinhole detective par excellence. Congrat, BTW, Guy, on Canada winning the ice hockey GOLD medal. Guillermo
Re: [pinhole-discussion] New image saloon uploaded on behalf of Pete Eckert
- Original Message - From: Sally Bowker bowk...@uwstout.edu Saloon is a great photo, evocative and inviting. Thank you for showing us! But I had to scroll to see the whole work, can you make it to fit on a monitor? You probably have a under 17 monitor. That image is in progressive format, but because the way the page is coded it isn't resizing as it'd normally do, otherwise. Try displaying the image alone buy clicking on this link: http://www.???/discussion/upload/images_2002/saloon.jpg
Re: [pinhole-discussion] Angle of ligh
- Original Message - From: Joao Ribeiro jribe...@greco.com.br The idea is producing a kind of a triptico (I don't know the name in English). Triptych
Re: [pinhole-discussion] Angle of ligh
- Original Message - From: ISHIKAWA Masaru mishik...@microhouse.co.jp I don't know how the angle of image cone is detemined. But I think it is equal to 2xArctan(d/t) where d is a diameter of pinhole, t is the thickness of pinhole-material. Masaru, You are right, that is de formula that defines the geometric cone, unfortunately, the USABLE image cone is much more smaller. That is why I disregarded pinhole thickness in my previous post. Nice ASCII drawings, Masaru! Guillermo
Re: [pinhole-discussion] HORSE, isn't it?
- Original Message - From: Richard Heather rheat...@slonet.org Guillermo, do you want a hung bao? Richard Heather (in-law to the Lo clan) Yes I do, I want a pinhole hung bao! Guillermo
Re: [pinhole-discussion] Angle of ligh
- Original Message - From: Joao Ribeiro jribe...@greco.com.br Now, what I intend to do is to place 2 sheets of film not at the end of the camera, but at the walls that are perpendicular to the pinhole plane. I imagine that the light absorbed by these walls will also form images, certainly distorted (I believe someone in this list have already done that). How far from the pinhole plane the film should be to be completely covered by light? My imaginations tells me that if it is too close I'll have a V shape image. Is this formula you sent me able to give me that info? I'm asking because it takes into account the film diagonal and I believe this cone is independent of the film diagonal, I'm not sure. Joao, It was, I believe, a bit hard to formulate the question without help of drawings, the case is the same for when stating an answer. Let me see if a can make sense of what I am thinking, when I put it in writing: As you know, COS^4 law dictates the fall off at the edges of a FLAT film plane NORMAL (90 degrees) to the lens axis (pinhole, ZP or glass). There are 3 factor that make up the factor for off lens axis imaging, namely: 1) The round pinhole looks like an oval whose size decreases by a factor of COSine of the angle 2) The maze of light fall obliquely on the film plane, therefore covers and area 1/COSine larger and finally 3) the distance pinhole film increases by a factor of 1/COSine, which translates into a lose of light of 1/COS^2 (due to inverse square law). All the above adds up to the well known COS^4 LAW factor and for your particular application, is valid for calculations of the fall off on the base of the camera. For the fall off on the walls of the camera we have to make some analysis: 1) the round pinhole still looks like an oval as we climb the wall starting from the base, that give us a factor of COSine of the angle in light lose, as above. 2) The maze of light stills falls obliquely, but this time the film plane being vertical rather than horizontal causes the lose of light to be proportional to 1/SINE of the angle, rather than 1/COSine as above. 3) and finally, the distance pinhole to (vertical) film plane increase changes at a rate of K / (2 * SIN of angle) , where K is the amount of times the focal length fit in the base of the camera, in other words, in the width of the film plane. All the above adds up to a factor of: Light fall off FACTOR = [ 4 * SIN^3 (angle) * COS (angle)] / K^2 (sorry I didn't simplify the above a bit more, but what I remember of my grade 8 trigonometry class does not help, probably it does not allow more simplification, but if someone out there thinks otherwise, I'd love to know how) You could use the above FACTOR result to find out the number of stops that angle will cause as light fall off on the camera walls. Number of fall of stops = [LOG ( 1/ FACTOR )] / 0.3 BTW, it's been said that for flat film planes the maximum image circle is 3.5 times the focal length of the camera. In such a camera, the fall off at the extreme edges would be 4 stops with respect to the center of the film plane. I mention this in case you want to find the angle that causes a similar fall off on the edges of the walls. Hope it helps Joao. (Answer is open to corrections) Guillermo
Re: [pinhole-discussion] HORSE, isn't it?
- Original Message - From: ISHIKAWA Masaru mishik...@microhouse.co.jp Celebrating Chinese New Year, a Year of Horse. (Unfortunately Asian not always understand Chinese. ) Kung hei fat choi is virtually universal these days, no need to be Asian Cantonese speaking person to know that's the Chinese-Cantonese new year greeting, at least that is true in very cosmopolitan cities like Toronto where I live, anyway. I'll say it in English then: Congratulations, Make money Now, I am single (;-), if you are married, pls send me a red envelope with an even number of pinhole images, except 4, that's bad number in Chinese traditions! Keep the envelopes coming, pls. :-) Guillermo
Re: [pinhole-discussion] Angle of ligh
- Original Message - From: Joao Ribeiro jribe...@greco.com.br When the light enters the camera, it enters in an angle the depends on the pinhole diameter or this angle is constant? Imagine I have a pinhole of 0.5 mm. If I make a bellows camera and set it to say 50 mm focal distance using an 8x10 film I'll have a very wide angle image. But if I enlarge the bellows distance to 500 mm I'll then have a telephoto image. Well, actually the image cone will be the same, I'm just choosing a section of the cone farther away from the pinhole or origin, and I am also selecting part of this cone to be recorded. How can I calculate the cone angle? Will changes in the pinhole diameter make any difference in this angle or it will always be constant? Joao, Geometrically/mathematically speaking, the angle changes when the pinhole diameter changes, the change is so small tho, that in practice you can dismiss it. Since you want to calculate the cone angle, otherwise known as angle of view, here is a formula I just derived that takes the pinhole diameter into consideration: Cone angle = ArcTan [ (D+P) / (2 * B) ] Where D = Diagonal of your film format P = Pinhole diameter B = Bellows extension (or focal length) As you can see, the effect of adding P to D is very small, i.e., for 8x10, D would be equal to about 325mm if you add to that a P of 0.5mm, you get 325.5mm, again, not a big change. The same happens if you change the pinhole diameter. Guillermo
[pinhole-discussion] HORSE, isn't it?
Kung hei fat choi !! to all our Asian friends in this list. Guillermo
Re: [pinhole-discussion] list is fine (?)
- Original Message - From: jaugusta jaugu...@adelphia.net Hello! Newbie here, just getting my first posts all of which ask why no one's posting! Is this a joke? Yes and no! This list goes into remission for couple of days from time to time. Usually hapens around holidays, I guess we can consider the Olympics as holidays!!. Having said that, this list is quite prolific, a quick look to the archives would confirm that. Well, I'll ask a question then. I removed the lens from a $2 35 mm camera and replaced it with a pinhole I made with the usual size 10 needle. Fuzzy heaven! Way past interesting distortion too! Anyone have a (not so technical) way for making a pinhole camera out of a cheapo 35 mm CVS special? I'd guess that camera has a focal length of between 35mm and 50mm, a better needle to use to make the pinhole would be a #15. You already managed to remove the lens, install a pinhole and make images with it, you already modified, successfully, your CVS, what you need to do is to make a new pinhole with a #15 needle and give it another try. BTW, I'd use a f/stop of f/180 if the pinhole is made with the #15 needle. Guillermo
Re: [pinhole-discussion] Pinholing with SLR and extension tubes
- Original Message - From: Dennis Johanson dennis.johan...@telia.com since I believe that a thin pinhole cap makes more sharp pictures. The pinhole itself does not need to be made on the cap (unless that's what you want). The pinhole can be made using thin material (0.002 shim stock for instance) and then tape it on the center of a hole you make on the cap, this hole has to be big enough so its walls do not cause vignetting (again, unless that is what you want). Guillermo
Re: [pinhole-discussion] Pinholing with SLR and extension tubes
- Original Message - From: Dennis Johanson dennis.johan...@telia.com This week I got an old SLR back from service, and I have a set of extension tubes for it. An idea came to my mind, namely to use one or more of the extension tubes with a pinholed lens cap or aluminum foil at front. Probably someone has tried this already, and if so I would be very interested in learning the outcome of it as well as in getting some suggestions for improving my idea. Dennis, You are right, it has been tried before. Some people lacking ext.tubes have even used toilet paper inner cardboard rolls (or similar rolls) or PVC/ABS tubes. Ext.tubes are really convenient as you can use a lens cap, as you mentioned. Your idea is OK, IMO. As for the outcome, it'd depend on what you are looking for. Resolution on film won't be as good and enlarging the frame willl make it worst (or better if that is what you are after). The best way is to try it out myself, but hey, I am the guy presently converting a (too small) guest toilet into a darkroom, So many things to do, so little time, I know what you mean. Guillermo
Re: [pinhole-discussion] Agradecimentos - Antes tarde do que nunca :) (Cleber)
- Original Message - From: Uptown Gallery mur...@uptowngallery.org I can't read Portugese, so I didn't know if this was intended for the pinhole list, but I did find the word 'pinhole' at the end of Cleber's posting I don't read Portuguese either but being somewhat similar to Spanish I am able to understand the core of the message, he mention: To be very satisfied with the postcards he has received from so many diverse places of the world. Beautiful images. The idea is good. He hopes it can be repeated some other times. He suggest to make a swap of self-portraits and mentions that it'd be an excellent way to show our faces. He thanks to all who sent him new year cards, apologizes to those that did not received one from him and hopes not to disappoint you next time. He ends saying: Thanks to everybody. Peace, Love and lots of pinholes The above best read listening to the bossa nova tune FOTOGRAFIA from the great Brazilian composer Tom Jobim, here is a link to a MIDI version: http://www.fortunecity.com/tinpan/davis/62/fotograf.mid Guillermo
Re: [pinhole-discussion] Art 21: Ann Hamilton
- Original Message - From: Lisa Reddig l...@julianrichards.com There have been a number of well known photographers who have done sneeky pictures like that. (My favorite Harry Callahan to name one) The dillemma as always with these kinds of things is the moral one. I know legally people in public can be photographed legally. But I would feel paranoid doing it secretly. Too much stress. I just picked up from the post office a polaroid back I bought that I plan to convert to pinhole camera and use 665 film in it. This camera has a side-wise pointing lens at a distance of about 100mm from the film with a mirror at 45 degrees in between http://members.rogers.com/penate/cameras/polback.jpg , first I thought to make it more wide angle, something like 50mm, but then I thought I could leave it as it is (just replace de glass lens with a pinhole) and use for candid/spy shots. I was surpriced to open my mail and find this thread! I am also reluctant to photograph people in public w/o their consent. I have done it sometimes with a pinhole/TLR, I look 90 degrees from the people but point the lens to them, this technique would be too obvious for some people being photographed as the front of the camera with the viewing lens is aimed to them. I could probably install a prop lens in front of the above polaroid back and the pinhole at the side, that would make it very effective for the purpose. Kind of like stealing a grape at the fruit stand, it doen't really matter, but it stresses me out because of the minute possibility of being caught. I call than sampling the grapes. Samplers and non samplers pay for that cost, as merchants make provisions for certain percentage of the grapes to never reach the scale/cash register. BTW, I'd recommend not to do it, hygiene being one of the reasons (but this is a topic for a different list :-). Guillermo
Re: [pinhole-discussion] Help for the new experimenter
- Original Message - From: Tim Midkiff ku...@vci.net Where I need help in getting started is finding information on making-buying-using, a cap in an old minolta slr I have. This would allow me to process film in the darkroom at the university I have access to. BTW, i'm a 37 year old kid. Could someone please direct me to a good beginning point? You can make it yourself as Andy explained it to you or you can kiss goodbye some 45 bucks and get it from http://www.pinholeresource.com/products.html#bodycap G.P
Re: [pinhole-discussion] Macro Pinhole Photos
- Original Message - From: Markus Birsfelder b...@freesurf.ch I used my Nikon camera with a body cap fitted with a hole approx. 2.5 mm. With a focal length (distance of hole to filmplane) of approx. 50 mm, Are you sure it was 2.5mm? That pinhole size would be infinity-optimum for a camera with a focal length of 15 feet (much longer for close up). BTW, I am curious about what your fellow club members thought or your approach and results. Guillermo
Re: [pinhole-discussion] (no subject)
- Original Message - From: Kosinski Family zin...@telenet.net all this left right up down is a little dyslexic, especially if you can't see, I suggest to you that blind persons are probably better at this dyslexic matters than people with good eye sight. Besides, whether you are able or not to see, when loading film (ortho film under safelight excluded) everybody is blind, after all, we have to do it under total darkness. so here is a tactile way to identify the emulsion side... the emulsion side will absorb moisture so just hold your finger on it for several seconds and it will feel sticky... this goes for paper, too You may be right, but why (IMO) ruin a sheet of film by planting your fingerprint on it. As someone already pointed it out, the notches are there to ID the film type and to tell you which is the emulsion side of it. Use the notches. Guillermo
Re: [pinhole-discussion] Hello...
- Original Message - From: Bob b...@fatboab.org Anyway, I've got plans for 5x4 and 10x8 pinhole cameras plus some shims to make the pinholes from. What I would like to do though is some panoramic pinholes in a 6x17 sort of format. I'm not the biggest fan of light fall off at the edges so I was wondering how to make a 6x17 camera fro scratch? Can anyone point me to some plans, or similar cameras that I can get inspiration from? If you don't like fall-off at the edges, you have two options: -make the angle of view no more than 70 degrees or -make the film plane conforming to a circle and the pinhole situated in its center. The difficulty with roll film cameras from scratch is the film winding mechanism. For flat film plane inspiration, just take a look to your 6x9. For semi-circular film plane cameras take a look to Doug Bardell's site from which you can also buy plans for a fairly large list of cameras of his creation. http://www.cyberbeach.net/~dbardell/index.html Guillermo
Re: [pinhole-discussion] Re: Silver Gem
- Original Message - From: Guy Glorieux guy.glori...@sympatico.ca Hi Zernike, I feel sorry for you on this. It is very disgracefull. Zernike, I'd suggest that before you start paying high BSL fees (BSL=blood sucking lawyers), you should get hold of one of the suspect cameras and make sure they in fact are infringing any patent you may have, as they may be may be morally guilty but legally right. I have never seen the inside of any of your beautifully looking cameras, but I'd say that one thing it can set yours apart is the film winding mechanism and the sliding thing at the rear of the camera to cover/uncover the frame counters for the different formats. They seem to have made changes in an effort to differentiate theirs from yours (how legally successful, that is the question). For instance yours seem to have the exposure wheel on the camera itself, theirs may be separate. Theirs shutter is different that any of the versions you sell them with. And I'd guess they have made some small changes to the winding mechanism and the frame counter cover, too (although they don't show a picture depicting the camera back in their web site. If they in fact are legally wrong, get them and get them well! Guillermo
Re: [pinhole-discussion] Re: Silver Gem-
- Original Message - From: Zernike Au zern...@zeroimage.com I am now looking for a lawyer in the England, any friends from England can introduce one to me please help. Go get them cowboy! Guillermo
Re: [pinhole-discussion] transparency film...xray duplication film
- Original Message - From: Andy Schmitt aschm...@warwick.net I bought some Kodak Contact 2000 film that requires other than Daylight or Tungsten enlarger light...pitty 'cause it was cheep...wonder why? Think I saw itwasn't Clinton Mandela the guy selling it?...may be not! :-) I have done my share of OOPS!...is not/doesn't do what I thought purchases, myself (to not fault of the seller, I must say). Guillermo
Re: [pinhole-discussion] intrododuction Frans van Dijk
- Original Message - From: Frans van Dijk digdi...@wxs.nl Since I whould like to share some images with you (one images is a thousand words) and get your comment on them, I tried to upload some files however I don´s come through. Can anyone give me some aid. I do have a password, and my files are under 50 kb. Frans, The process is very simple, you go to http://www.???/discussion/upload/upload.php and then fill in the blank with the FULL PATH of the image file you want to upload, or better, just click on the BROWSE button and navigate within your disk drive until your image file name is displayed, double click on it and finally select UPLOAD. Now, the last image in the gallery is francis6.12.jpg, if that is you, then, obviously the upload is working. Otherwise, give it a try again, if it fails and you'd like, send me the image files attached to an email to: pen...@rogers.com and I will upload them for you. Guillermo
Re: [pinhole-discussion] focusing zoneplates
--- Gordon J. Holtslander hol...@duke.usask.ca wrote: I'm going to try making some zoneplates. I've read about that zoneplates require focussing. None of my cameras pinhole cameras can focus. Is zoneplate focusing necessary in all cases? Is focusing needed only for subjects that are close to the camera? Does it matter whether a positive or negative image of the zone plate is used? Does the center circle have to be opauque? Here is what I think: Unlike pinholes which are a-focal, zoneplates do focus light by virtue of diffraction, therefore, technically speaking you 'd need to focus them. In practice, it is so difficult to do it and according to my tests, unnecessary. Just make the ZP for the infinity focusing distance, mount it at a distance equal to the focal length used to calculate it and that should work for shooting distances of 2 or 3 feet to infinity. About your second question: ZP work by suppressing destructive diffraction by consecutive rings. As long as we blacken every other ring, the constructive diffraction should happen, no matter the order (clear or dark center ring). Having said that, IMO, a better image can be obtained (haven't really experimented) by having a clear center ring. After all, the clear center ring is nothing but a pinhole, so we have a pinhole image (good geometric image) and a superposed diffraction image that makes the lens faster and have the characteristic glow of ZPs. Guillermo
Re: [pinhole-discussion] new postages
- Original Message - From: Guy Glorieux guy.glori...@sympatico.ca Nice pictures, Hughes. I was absolutely amazed by the beauty of your hand built cameras. Everybody on the list, don't miss it: it's a source of great inspiration as to what someone can do with a little bit of skill. I agree on the beauty of Huges' cameras. Not to discourage anyone, but I'd say a lot more than a little bit of skill is needed and a good set of tools, of course. If I had only showed interest and had learned my father's unmatched (IMO) fine carpentry and cabinetmaking skills :-( Guillermo
Re: [pinhole-discussion] Close-up pinhole photography
- Original Message - From: ROGER ARMOUR ro...@rharmour.fsnet.co.uk Thank you Guillermo and Bill for your comments. How do you make pinholes as small as 0.035 mm Guillermo? Thanks Roger, If you really mean 0.035mm, I can not make them that small, couldn't use them if I could make them, actually. The optimum focal length for such small pinhole would be around 0.9mm! The smallest pinhole I have made is 0.004 or 0.1mm. Independently of the size, my technique uses brass 0.002 thick for pinholes above 0.0065 pinholes and brass 0.001 thick for under 0.0065 ones. For very small holes, I use sharpened needles (sharpening done using 600 grit black sand paper), rest the center of the brass on my left index finger and the needle on point I want the pinhole to be, applying some pressure and rotating/drilling action at the same time until I start feeling the tip of the needle on my left index finger. I then sand the brass using 600 grip sandpaper, apply some canned air and check the pinhole with a measuring microscope. Invariable, the pinhole would have lots of burrs and not the required size. I sharpen the needle again and keep working on the hole in the same way as described until I get what I am looking for, the only difference is that sandpaper is used only the first time and a pencil eraser for the rest. Guillermo
Re: [pinhole-discussion] 12 day exposure
- Original Message - From: George L Smyth glsm...@yahoo.com When I go to that link, I am redirected to http://www.p at ???/discussion/. Here is the direct link to B.E excellent image: http://www.p at ???/discussion/upload/gallery2001.php?cmd=maxstart=pic= bathtub_copy.jpg Guillermo
Re: [pinhole-discussion] oops.. wrong fixer dilution...
- Original Message - From: R Duarte ra...@rahji.com what's going to happen? will the film police come after me? is my family going to suffer dire consequences because of my stupidity? and how do you all keep track of 2 dilutions of fixer, When using Ilford Universal Fixer, I use film strengh for both film and paper, with the added advantage that paper (RC) fixes in just 30 secs. anyway, let me know if there's anything i can do or if i should just deal with the fact that these negatives are going to discolor over time or something. (how long do they have if that's the case?) I am not sure if you said you fixed them for 12 minutes using 1+7 (twice during 6 minutes each time), if so, you should be OK, otherwise, you could still re-fix them using the correct dilution and for 60% or so of your normal time for film [ 1 minus (1/7)/(1/3)]. Guillermo
Re: [pinhole-discussion] loading paper into a cancamera
- Original Message - From: Tom Miller twmil...@mr.net Another thing I've done with small can cameras is glue a strip of mat board to the inside of the can on either side of where the paper should be. This was with a cylinder camera using film for negatives and the force of the film wanting to make itself flat again held the film in place. This should work with paper, too. That is a good method, an improvement can be made by making a beveled cut on one of the edges of each strip and install the strips with the beveled egde facing each other. Alternatively, 2 strips can be glueed together the one directly glueed to the can narrower that the top one, this will form a slot on which you slide down the film or paper. A even quicker method if your can is made of ferrous material, is to use plain flat magnets (the stronget the better), either right on top of the edges of the film/paper or instead of the mat strips as above. I can almost smell the turkey!! and turkey again next day, and the turkey sandwhich the day affter, and the the turkey soup and the turkey...on and on and on!! It is a good thing thanksgiving (mid Oct) is not as close to Xmas here in Canada!! Anyway, Merry Xmas to everybody. Guillermo
