A Mamiya Lens...

penst said:
Thats not exactly what I meant. I was wondering what the method or calculation formula was to figure out what the "look" will be compared to the "full" 35mm film or sensor size comparison we are used to making. I figured it out. Actually because this is a 645 format lens an 80mm in my case is roughly double the 1.6 or a 3.2 "crop factor" to effectively make the lens appear like a focal length of 240-250mm mated to the APS-C sensor in the 7/550d's. Right?
Click to expand...

Which frame of reference are you using, 35mm or 645?
 
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penst said:
I don't understand this question.
Click to expand...

The crop factor when comparing APS-C to 645 should be 2.6x. I calculated using the diagonals.

Why the diagonals? Well, in still photography, a "normal lens" is technically defined as a lens with a focal length equal to the diagonal of the image format. For 645, "normal" would be 69.7mm, and for APS-C, "normal" would be 26.7mm. At these focal lengths, the FOV would equal, so then every focal length for APS-C would be multiplied by 2.6 to get focal length for the equivalent FOV on 645.

BTW, the technically defined "normal" focal length for full-frame is 43.3mm. By lens maker convention, that's rounded up to 50mm.
 
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One of the few IMO advatanges of using 645 lenses on smaller chipped cameras is the images circle allows huge options for shift and tilts

the crazy adpater guy is..

http://www.zoerk.com/

In the extreme..

Mini-view_EOS.jpg


S
 
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