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SLR lens to C mount


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#1 andrew parrish

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Posted 01 July 2010 - 08:35 PM

Sorry if this is a redundant question. I could not find a thread with the search engine. I am thinking about moving out of the hobby type super camera, into some thing that has some more features, like inter-changeable lens. However, popular opinion ( I could be wrong) seems to be that using non 8mm lens, like 16mm and 35mm lens, is really going to compromise the image quality. I have read that the lens can be adjusted ( re-culminated?) to work better. Is this true? and if it is, what does it cost, and who does it best?

Thanks for your Time ( patience)
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#2 Saul Rodgar

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Posted 01 July 2010 - 09:19 PM

Sorry if this is a redundant question. I could not find a thread with the search engine. I am thinking about moving out of the hobby type super camera, into some thing that has some more features, like inter-changeable lens. However, popular opinion ( I could be wrong) seems to be that using non 8mm lens, like 16mm and 35mm lens, is really going to compromise the image quality. I have read that the lens can be adjusted ( re-culminated?) to work better. Is this true? and if it is, what does it cost, and who does it best?

Thanks for your Time ( patience)


I am not sure I understand your question. You are talking about using larger format lenses on smaller gauge film / sensor and the image quality being compromised because of it? If that is the case, the field of view (FOV) will change (narrow) the bigger format lens you use, usually and roughly it will double the FOV for a 16mm lens image on 8mm, or a 35 mm lens image on 16mm.

If the lens adapters are well made, further adjustments won't be necessary, unless you intend to pull focus using the lens barrel marks only , in which case, yes you would have to re-collimate the lens. Additionally there are other instances for which you would need to collimate the lens:

http://lavender.fort...ollimation.html
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#3 andy oliver

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Posted 02 July 2010 - 07:33 AM

Sorry if this is a redundant question. I could not find a thread with the search engine. I am thinking about moving out of the hobby type super camera, into some thing that has some more features, like inter-changeable lens. However, popular opinion ( I could be wrong) seems to be that using non 8mm lens, like 16mm and 35mm lens, is really going to compromise the image quality. I have read that the lens can be adjusted ( re-culminated?) to work better. Is this true? and if it is, what does it cost, and who does it best?

Thanks for your Time ( patience)



Hi, i did mess many years ago with a pentax 50mm f1.7A lens on an R16 via an adapter, the resolving power of the lens was poor when compared to a proper 16mm lens on the camera ( namely the schneider cinegon 25mm f1.4 ).
Unless you require longer focal lenghts on the camera, i would be inclined to stick with super 8 lenses designed for the camera.
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#4 Saul Rodgar

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Posted 02 July 2010 - 01:57 PM

Hi, i did mess many years ago with a pentax 50mm f1.7A lens on an R16 via an adapter, the resolving power of the lens was poor when compared to a proper 16mm lens on the camera ( namely the schneider cinegon 25mm f1.4 ).
Unless you require longer focal lenghts on the camera, i would be inclined to stick with super 8 lenses designed for the camera.


Since the center part of the (larger fomat) lens is usually sharpest, which is the part of the lens that you would use if you used it with a smaller format camera, I think there was something else going on there. I have many 35mm lenses (including a Pentax f1.4 50mm prime) that I use on R16 and S16 (but not 8mm) with outstanding results. Your adapter and / or lens were likely faulty.

If the lens, the adapter and the camera are all in good shape, the larger format lens will very likely work on smaller gauge cameras, barring some back focus / flange focal issues or other well established problems. One shouldn't just say "I had a bad experience once with a similar set up, you may want to avoid it altogether" when it has been proven to work elsewhere. For example, 35mm still Canon EF lenses are perfectly usable with XL 1/3" cameras (close to the 8mm frame size) with the right adapter.

Edited by Saul Rodgar, 02 July 2010 - 01:57 PM.

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#5 andrew parrish

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Posted 03 July 2010 - 05:00 PM

Thanks for the replies Roger and Saul. The link to the Baumgarnder article was very helpful, as were your coments. With the right terms, and your help,I think I have a much better understanding.

Thanks,

Andrew
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#6 andy oliver

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Posted 04 July 2010 - 05:08 AM

Since the center part of the (larger fomat) lens is usually sharpest, which is the part of the lens that you would use if you used it with a smaller format camera, I think there was something else going on there. I have many 35mm lenses (including a Pentax f1.4 50mm prime) that I use on R16 and S16 (but not 8mm) with outstanding results. Your adapter and / or lens were likely faulty.

If the lens, the adapter and the camera are all in good shape, the larger format lens will very likely work on smaller gauge cameras, barring some back focus / flange focal issues or other well established problems. One shouldn't just say "I had a bad experience once with a similar set up, you may want to avoid it altogether" when it has been proven to work elsewhere. For example, 35mm still Canon EF lenses are perfectly usable with XL 1/3" cameras (close to the 8mm frame size) with the right adapter.


The 50mm f1.4 pentax lens is a better lens, there was nothing wrong with my lens or adapter. I also recall using a 50mm f1.8 canon fd lens, again this didn't really inspire me.
I did shoot some 'Concorde' footage during its last year of operations on the R16 via a leica 180mm lens, now that was razer sharp.

Amateur Photographer 50mm lens test from the 1980s gave the 50mm pentax 50mm f1.7a only a good rating on the optical quality, whilst nikon, leica and canon ( 50mm f1.4 ) faired a lot better.
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Media Blackout - Custom Cables and AKS

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