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Thread: Schneider 120mm Macro A/D and Image Circle size

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    Schneider 120mm Macro A/D and Image Circle size

    Does anyone happen to know the size of the image circle (IC) of the Schneider 120mm Macro Apo-Digitar when used at infinity (say, at f11)? From the specs on the web it appears that the IC size progressively decreases:

    At 4:1 [4x Life Size] - 110mm @ f5.6
    At 2:1 [2x Life Size] - 110mm @ f5.6
    At 1:1 [Life Size] - 110mm @ f5.6
    At 1:2 [1/2 Life Size] - 90mm @ f11
    At 1:4 [1/4 Life Size] - 80mm @ f11

    Cheers,

    Angus

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    Re: Schneider 120mm Macro A/D and Image Circle size

    Hi Angus,

    This is logical. The IC increases with the reproduction scale, respectively with the distance lens to image plane. Since it needs e.g. twice the length with a scale of 1:1 (distance lens to image plane = 2 x focal length) as for a scale a infinity (distance lens to image plane = focal length), the resulting projected image circle of the used lens increases in proportion.

    It doesn't really make sense to use this lens at infinity, since it's not its range of best reproduction quality. It is built and corrected for a range between 1:4 to 4:1.
    However, my guess is that at infinity the IC is around 70 mm.

    Thierry

    Quote Originally Posted by greygrad View Post
    Does anyone happen to know the size of the image circle (IC) of the Schneider 120mm Macro Apo-Digitar when used at infinity (say, at f11)? From the specs on the web it appears that the IC size progressively decreases:

    At 4:1 [4x Life Size] - 110mm @ f5.6
    At 2:1 [2x Life Size] - 110mm @ f5.6
    At 1:1 [Life Size] - 110mm @ f5.6
    At 1:2 [1/2 Life Size] - 90mm @ f11
    At 1:4 [1/4 Life Size] - 80mm @ f11

    Cheers,

    Angus
    Thierry Hagenauer
    [email protected]

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    Re: Schneider 120mm Macro A/D and Image Circle size

    Thanks Thierry. Rather than double-up with the normal 120, I thought I could use the macro version on the odd occasion that I needed a longer focal length in that range. From another thread I believe that the macro 120 performs better at infinity than the normal 120 does for close-up work. That said, 70mm doesn't leave a whole lot of room for shifting...but probably enough for my needs.

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    Re: Schneider 120mm Macro A/D and Image Circle size

    I was in the same boat as you a few months back and asked my dealer the same question and was recommended the normal version unless I needed <4:1 reproduction more often than infinity. The 120N is a very sharp lens with IMO a bigger than spec IC, however when used close up (as an estimate <100cm subject distance) its not as sharp and the macro would probably perform better.

    There are no specs on the lens performance at infinity as its not designed to be used that way and Thierry estimation is probably correct around the 70mm mark. One point of note is I think the macro is designed to be used at optimum f stop of f8 (f5.6 above lifesize I think) where as the 120N can go down to f11. Not so much a problem on a bellows camera but could be an issue on a pancake type.

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    Re: Schneider 120mm Macro A/D and Image Circle size

    Which one (if any) did you go with in the end?

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    Re: Schneider 120mm Macro A/D and Image Circle size

    The normal 120N as I wanted the larger IC for movements and most of my "lifestyle" product type work is above 1:4 size.

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