Lens Questions: Ilex-calumet Caltar 10" (254mm) F6.3

[BenZucker]

I have a few questions about this lens. First of has any one used it, if so please share your general experiences with it. I am most concerned with finding out what the image circle is, I plan to use this on 8x10. Also I am interested to know what the sharpness fall off is like. I once used an Ilex 150mm that was of no use to me on 4x5 because the sharpness fell off so quickly from the center of the frame. I know that this lens is also mounted in a No.3 Acme Synchro shutter, can the cells from this be removed and put into a more modern copal 3 without modification/machining?

 

[David Lindquist]

I don't have personal experience with this lens but I have some information. My 1968 Calumet catalogue says the 254mm (10 inch) f/6.3 Ilex Caltar covers 64 deg "stopped down". Probably safe to say this would be f/16-f/22. Doing the trig, this gives an image circle of 317mm. This is less than the diagonal of an 8 X 10 piece of film (=325mm). Might just make it within the confines of the image size once the borders defined by the film holder are trimmed off. I don't have any experience that would allow me to comment on how much fall-off there would be at the extremes of coverage.

Despite having the same number designating their size, the No. 3 Acme and the No. 3 Copal are rather different The Acme is threaded 1.775" X 48 threads per inch; the Copal is 58mm x .75mm pitch.
David

 

[panchro-press]

I own one. It's a fine lens; but it will not cover an 8x10...trust me.

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