Bob Hayes Posted March 20, 2008 Share Posted March 20, 2008 I have a strange question. Some one told me that if I put a video lens on a film camera the colors will not all focus on the film plane because they are staggered to fall onto different chips. I thought the prism did all the separating and I also thought a lens was a lens. Granted some lenses have better quality and some are designed to hit a smaller target. I had never heard that video lenses behaved this way until recently. Link to comment Share on other sites More sharing options...
Premium Member Michael Nash Posted March 20, 2008 Premium Member Share Posted March 20, 2008 It's true. The prism does do the separating, but focuses each color at slightly different distances. 2/3" video lenses are calibrated for these distances, not a single focal plane. There's an adapter that corrects for this, which is what allows single-sensor cameras like the RED to use 2/3" video lenses. http://pro35.com/zgc.nsf/product/C1044112A...5256EC9005F5789 Link to comment Share on other sites More sharing options...
Mitch Gross Posted March 21, 2008 Share Posted March 21, 2008 It's true. The prism does do the separating, but focuses each color at slightly different distances. 2/3" video lenses are calibrated for these distances, not a single focal plane. There's an adapter that corrects for this, which is what allows single-sensor cameras like the RED to use 2/3" video lenses. http://pro35.com/zgc.nsf/product/C1044112A...5256EC9005F5789 Yes that's the Abekas device. They make one for Super-16 that corrects back for the color wavelengths and another for 35mm that does the same but also incorporates a doubler (2x magnifier) to cover the image area (and eat two stops of light). Abel has the S-16 unit in rental, which can also be used on a RED shooting in 2K mode. Link to comment Share on other sites More sharing options...
Evangelos Achillopoulos Posted March 21, 2008 Share Posted March 21, 2008 Where can I find more info about that ?difference? that 2/3 prism lens has? How much different they are or what is the result in use of flat photo lenses in prism based cameras? Do they introduce aberrations and what kind? Link to comment Share on other sites More sharing options...
Premium Member Michael Nash Posted March 21, 2008 Premium Member Share Posted March 21, 2008 Where can I find more info about that ?difference? that 2/3 prism lens has? How much different they are or what is the result in use of flat photo lenses in prism based cameras? Do they introduce aberrations and what kind? On a technical level, I don't know; wish I could help you. But on a practical level, you can't combine the different lens/camera formats without an adapter anyway, so you might as well use the right one... http://www.smsprod.com/products/lenses/angenieux4.html Link to comment Share on other sites More sharing options...
Mitch Gross Posted March 24, 2008 Share Posted March 24, 2008 Search the archives of this forum (cinematography.com), as well as cinematography.net and wikipedia. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now