Originally posted by moxfyre Also, taking a flower at 1:1 will NOT give you the same picture regardless of focal length!! If you do it with a 300mm macro lens, you'll have to put the camera about 5 feet away. If you do it with a 50mm macro lens, you'll have to put it about 1 foot away. The perspective will be completely different... the flower will look "flattened" with the telephoto lens, whereas it will look more 3D with the 50mm lens.
Oppss. Now the perspective comes back to haunt me
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I probably need to reread all of the definitions before I talk again
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However, when I reread the whole thread, what I (and possibly thepirate) refer as "reach" is just simply "magnification" by your definition. Since your definition said that magnification is defined by FL and CTS distance, that would explain the beginning of discussion about FF vs. crop sensor.
So if you keep the same FL and CTS distance, then the magnification stays the same when you move from FF to crop sensor. Of course, it also comes to the discussion of either the lens or sensor as the limiting factor.
I think you now clearly understand what I meant by "reach"
. Definitely not a conventional textbook definition.