Originally Posted by
steve simmons
Reproduction ratio is the size of the object in reality vs the size of the image on the gg. If they are the same it is 1:1 and the bellows extension will be twice the focal length of the lens.
Some people do the math, some use a device, me, I just measure the bellows. If I have extended it 25% longer then the focal length of the lens I add 1/2 stop, 50% more then the focal length of the lens I add one stop, 75% more I add 1.5 stops, and twice as long I add two stops.
Works every time.
I would not worry about any differences in repro ratio between the front and back of the subject.
steve simmons
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