Re: telecentric question

Dom Jaeger

On Fri, Mar 1, 2019 at 06:45 PM, Jeff Kreines wrote:
Have you had the chance to test any of the special Cooke Speed Panchros modified by Cooke for 3-strip Technicolor?  Those cameras had a huge prism block in the light path.
I wonder how some of the pellicle beam splitter BNC reflex conversions would affect image quality, since the BNCR lenses, unlike Bolex Rx lenses, weren’t designed to compensate for the beam splitter.
I've never encountered one of those Cookes, but I would make an educated guess that they were modified to compensate for the prism in some way. While researching Taylor Hobson history recently in an attempt to make some sense of the rather muddled dates listed on the Cooke history webpage I did come across a lens diagram of their retro-focus Technicolor 35mm in a Rank Taylor Hobson technical article from 1960 called "Achievement in Optics", which includes the prism as a lens element. It's only logical that they factored it in to any modifications they made to the other focal lengths. 

Pellicles, as used in the reflex converted Mitchell BNCs and other cameras, tend to be quite thin, so there is much less effect on the image. 

Dom Jaeger
Lens Technician
Panavision Melbourne

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