Re: [Cameramakers] Surplus Military lenses??
Mac wrote: How can I figure out the focus (bellow ext) needed to project the 120 neg to 48 with this lens? What is the math involved? ..Does this sound like it will work? project a 120 neg to 48 wide. Mac Hi there, I have built optical instruments before and have made the huge mistake of using a lens on the project just because you found it cheap. I do not know if this lens will work on your project.. I would say that the odds are that it will not Most glass lenses, and I believe plastic as well, act as tremendous Ultra Violet filters.. and they will block the necessary UV range that you need for exposure I am in the process of building a UV enlarger my self...What I found in my research is that El Nikor enlarging Lenses are made of a special optical glass that will pass the needed UV range up to 425 nm... Most other lenses and I believe plastic will stop the UV transmission dead in its tracks at about 200. On the Alt Photo list we had discussed this and a man took a El Nikor lens and tested it on a UV spectrometer and it verified what I am saying... If you are covering 6x6 format you will need a 80mm to 90mm lens and 6x7 format you will need 105 mm.. The shorter you can keep the focal length to your format the larger you can enlarge in a given distance I believe they make a special wide angle lens that will some what shorten the distance needed to project your image to a final 48 inches diagonal but they are very expensive lenses and I seldom have seen them for sale used... Most All El-Nikor enlarging lenses are a high quality 6 element lens and are usually f5.6 in the sizes we are talking about... They are usually under $50 on E-bay ... Also to enlarge to that huge size will require a very long exposure and you may find that the film can not handle the infrared heat as light fall off increases dramatically the larger you go. On my project I am trying to find out how to increase the speed of dichromate sensitized paper to reduce the time I need to expose... If you come across any information on this I hope that you would pass that along to me... I imagine you can just set up a standard medium format enlarger rigged with first surface mirrors to channel the sun light into the film chamber into a dark room or box if you are setting up a daylab deal you would have to block all light fom the film plane down to the paper plane ..I would not use the condensers as they too will block the UV as well as standard mirror Now you know everything that I know.. Good luck... Send me a picture of the thing when it is built Regards, John Cremati - Original Message - From: filmpro [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, August 08, 2002 11:48 PM Subject: Re: [Cameramakers] Surplus Military lenses?? Hello again! Found this TV projection lens: Does this sound like it will work? project a 120 neg to 48 wide. 4-1/2 DIA. FUJINON TV PROJ. LENS Item No.: L1812 Unused beauty. Fujinon TV projection lens Model #VP5110B. Designed for use in big screen TV projection systems. Multi-element coated acrylic lens system is made from optical grade methyl-methacrylate for image quality and light weight. Front element is 4-1/2 clear diameter, rear element is 4-3/8 diameter. lens projects a large image in a short distance. f/0.95. Great for education projects such as slide or transparancy projector, etc. Designed to be nearly in contact with subject surface, and will cover up to 4-1/4 diagonal source. 5-1/2 diameter by 8 long. Back end has outside threads. Includes front and back lens covers. http://www.surplusshed.com/pages/Lenses.html Thanks How can I figure out the focus (bellow ext) needed to project the 120 neg to 48 with this lens? What is the math involved? Mac ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
Look at Surplus Shed for military lenses. I would look for something with larger aperture (not a Metrogon) and normal viewing angle. You might also look for projection lenses of the kind used for opaque projectors (I doubt anyone makes these anymore and probably few persons still use them, so you might be able to buy a projector or lens cheaply.) These had reasonably long focal lengths, were corrected for less than infinity object distance and had fair aperture (maybe F4 or so). You might look at Fresnel lenses as condensers. Bob At 20:24 08.08.02 -0700, you wrote: Greetings! I have a project and would appreciate some suggestions. I need to build a SOLAR ENLARGER. Basically a Daylab type enlarger, that can project a 120 negative (in a glass holder) onto a surface as wide as 48. The light source will be the sun. the reason, i need to expose a cyanotype print. I would like to find a surplus lens, maybe a military arial type lens? Any advice or where to look? What about focusing? I was also thinking that I could use mirrors to focus more light into the enlarger. Any ideas? i can't contact print the cyanotype with an enlarged neg because the surface is not flat. Thanks Mac ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
Hi! I bought one of the lights at Walmart. Ised it in a cardboard box to expose my printing frame works well. Still i don't think you can beat the sun we have here in California. I will try a test. Will report back. Mac You would break the outer envelope being careful not to damage the inner parts, which include a high pressure, quartz, mercury vapor bulb. Quartz passes the UV. You must NEVER look at this for extended times without a filter against UV exposure to your eyes and skin. A piece of conventional glass will remove most of the problem UV while leaving the useful stuff. I believe you can also buy versions of this lamp without the fluorescent coating and then it is better NOT to remove the outer envelope. This may be harder to find. IMPORTANT details: 1) Never touch the bulb or clean well if it accidently happens. The bulb becomes very hot and the dirt (oil, salt) from your skin will burn on and speed the failure of the lamp. 2) these bulbs can explode and throw hot quartz all over. Use a shield to contain the pieces in case it happens. I have used a laboratory beaker for this but something thicker would be better, and I suggest metal in every direction except the way to the film, condenser and whatever. 3) The lamps contain mercury and if one explodes you should have a system to vent the vapor outdoors and trap any liquid (the shield should be able to do this.) You take a grave risk by not protecting you and everyone else from such a source. ### Can you not hold the fabric flat during a contact exposure! You can then enjoy the full power of the sun. Good luck, and think about safe methods. There is little danger if you stay clever. Bob ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
Hi Mac, I had some after thoughts .First I just wanted to add a disclaimer.I have not built and tested my UV enlarger yet so I can not tell you if everything I told you is 100 percent correct. This is uncharted territory for me as well... I am not real familiar with your process so I do not know the UV sensive range that you require or if in fact that UV plays a part at all( all you may require is the visible spectrum of light , in which case any lens would work and everything I have told you would probably not apply... I have heard that Ansel Adams built some sort of special enlarger but I have not been able to check that out yet Some other thoughts : If you are sun exposing you may have to fiddle with the enlarger to track the sunAlso if you are projecting on to a uneven surface you may have to stop your lens down quit a bit to have everything in focus.. As far as a glass negative holder , again , regular glass is a powerful UV filterI would go to Optical white glass that is listed below for your negative holder. ( It may be the glass that Nikon uses in their lenses.) You may want to try a sandblasted upper glass on the holder to act as a diffuser.. I think it may cut down the light output , but would give a more even distributionTry it both ways.. Here is a dealer that sells the Schott Optical White Glass B270, It comes in all thickness. It supposedly has a very high UV transmission rate comes in large sheets and is reasonably priced . It would be good for large contact frames, film holders ect.. http://www.howardglass.com/B270.html The light source I will be using is a 5000 to 10,000 watt pulsed xenon light headSupposedly a good source of UV... I am just going to use a blower fan to keep things cool... Happy Trails, John Cremati - Original Message - From: filmpro [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, August 09, 2002 4:23 AM Subject: Re: [Cameramakers] Surplus Military lenses?? Hi john! Very helpful. I don't have a problem getting a Nikor lens. i was under the impression one of these large lenses would put out a lot more light (f 1). I did realize the plastic elements would probably block the UV. Yes, I do expect a very long exposure.I'm guessing a 20 min Cyanotype contact print would take a couple hours with the solar enlarger. Well, i might have to rig the glass neg holder to a large metal heat sink and some how cool it with ice. I do expect this would be a disposable copy neg for my process. What UV source are you trying to use? i figured the sun would pump a lot more UV than any light source. I need to print on a irregular fabric. Thanks Mac Also to enlarge to that huge size will require a very long exposure and you may find that the film can not handle the infrared heat as light fall off increases dramatically the larger you go. On my project I am trying to find out how to increase the speed of dichromate sensitized paper to reduce the time I need to expose... If you come across any information on this I hope that you would pass that along to me... I imagine you can just set up a standard medium format enlarger rigged with first surface mirrors to channel the sun light into the film chamber into a dark room or box if you are setting up a daylab deal you would have to block all light fom the film plane down to the paper plane ..I would not use the condensers as they too will block the UV as well as standard mirror Now you know everything that I know.. Good luck... Send me a picture of the thing when it is built Regards, John Cremati ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
Another thought... If you are exposing for a long period of time the position of the sun may play a huge factor on your enlargement with out a condenser. Take a flash light and move it 25 degrees across film and see what it does to the final image on the wall... A guess would be that the image will move right along with the light thus ruining your print... John - Original Message - From: filmpro [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, August 09, 2002 4:23 AM Subject: Re: [Cameramakers] Surplus Military lenses?? Hi john! Very helpful. I don't have a problem getting a Nikor lens. i was under the impression one of these large lenses would put out a lot more light (f 1). I did realize the plastic elements would probably block the UV. Yes, I do expect a very long exposure.I'm guessing a 20 min Cyanotype contact print would take a couple hours with the solar enlarger. Well, i might have to rig the glass neg holder to a large metal heat sink and some how cool it with ice. I do expect this would be a disposable copy neg for my process. What UV source are you trying to use? i figured the sun would pump a lot more UV than any light source. I need to print on a irregular fabric. Thanks Mac Also to enlarge to that huge size will require a very long exposure and you may find that the film can not handle the infrared heat as light fall off increases dramatically the larger you go. On my project I am trying to find out how to increase the speed of dichromate sensitized paper to reduce the time I need to expose... If you come across any information on this I hope that you would pass that along to me... I imagine you can just set up a standard medium format enlarger rigged with first surface mirrors to channel the sun light into the film chamber into a dark room or box if you are setting up a daylab deal you would have to block all light fom the film plane down to the paper plane ..I would not use the condensers as they too will block the UV as well as standard mirror Now you know everything that I know.. Good luck... Send me a picture of the thing when it is built Regards, John Cremati ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
Another thought... If you are exposing for a long period of time the position of the sun may play a huge factor on your enlargement with out a condenser. Take a flash light and move it 25 degrees across film and see what it does to the final image on the wall... A guess would be that the image will move right along with the light thus ruining your print... John I thought about that, but there would be a piece of diffused glass between the sun and neg. ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
? A proper lens takes the light coming from the object (the film in this case) and projects it in a way such that all light coming from a single point, whatever its direction of travel, will end up at a single point on the image (the fabric). Assumed is that the system is correctly focused. Wandering of the sun does not change this; a single point on the source will be projected to a single point in the image throughout the wandering of the sun. However, there is a different trouble; rather quickly the sunlight through a given point will not hit the lens so that point in the image will go dark. The nicest solution is what I believe is called a heliostat. This has a mirror which tracks the sun's motion in a way so the light is cast in the direction of the lens a the sun wanders through the sky. You could do it by hand until you determine whether making a real tracking machine is worth the bother. Please note, the sunlight comes from a constant direction when this device is in use, no matter where the sun actually is (if not below the horizon or behind a cloud!) There is a different problem as well. You more or less need a condenser unless the lens is bigger than the film. Sunlight travels as a nearly parallel bundle of rays. Only light passing through a circle the size of the lens but lying in the plane of the negative actually passes through the lens. You can move this circle over the film but only this much negative is being exposed at any time. Without a condenser you will have to scan the film by passing the light from various directions through the lens so the whole film is roughly equally sampled. I suggest adding apiece of heat absorbing glass if you can find one in the right size; for a 2x2 negative it should be relatively easy. Bigger will be harder and more expensive. Bob At 08:49 09.08.02 -0700, you wrote: Another thought... If you are exposing for a long period of time the position of the sun may play a huge factor on your enlargement with out a condenser. Take a flash light and move it 25 degrees across film and see what it does to the final image on the wall... A guess would be that the image will move right along with the light thus ruining your print... John I thought about that, but there would be a piece of diffused glass between the sun and neg. ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
Diffusion glass will do the job as well but with the cost of considerable light loss, which might be important when exposures are getting to look like hours. Bob At 08:49 09.08.02 -0700, you wrote: Another thought... If you are exposing for a long period of time the position of the sun may play a huge factor on your enlargement with out a condenser. Take a flash light and move it 25 degrees across film and see what it does to the final image on the wall... A guess would be that the image will move right along with the light thus ruining your print... John I thought about that, but there would be a piece of diffused glass between the sun and neg. ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
Diffusion glass will do the job as well but with the cost of considerable light loss, which might be important when exposures are getting to look like hours. Bob Thanks for the info. I will do some tests this coming week. Would be interesting to find out the ratio it will take an enlarged neg to expose the paper as opposed to contact. I guess one could calulate it, but I will just do some real world tests. Mac ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
[Cameramakers] Surplus Military lenses??
Greetings! I have a project and would appreciate some suggestions. I need to build a SOLAR ENLARGER. Basically a Daylab type enlarger, that can project a 120 negative (in a glass holder) onto a surface as wide as 48. The light source will be the sun. the reason, i need to expose a cyanotype print. I would like to find a surplus lens, maybe a military arial type lens? Any advice or where to look? What about focusing? I was also thinking that I could use mirrors to focus more light into the enlarger. Any ideas? i can't contact print the cyanotype with an enlarged neg because the surface is not flat. Thanks Mac ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Surplus Military lenses??
Hello again! Found this TV projection lens: Does this sound like it will work? project a 120 neg to 48 wide. 4-1/2 DIA. FUJINON TV PROJ. LENS Item No.: L1812 Unused beauty. Fujinon TV projection lens Model #VP5110B. Designed for use in big screen TV projection systems. Multi-element coated acrylic lens system is made from optical grade methyl-methacrylate for image quality and light weight. Front element is 4-1/2 clear diameter, rear element is 4-3/8 diameter. lens projects a large image in a short distance. f/0.95. Great for education projects such as slide or transparancy projector, etc. Designed to be nearly in contact with subject surface, and will cover up to 4-1/4 diagonal source. 5-1/2 diameter by 8 long. Back end has outside threads. Includes front and back lens covers. http://www.surplusshed.com/pages/Lenses.html Thanks How can I figure out the focus (bellow ext) needed to project the 120 neg to 48 with this lens? What is the math involved? Mac ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
