Can someone explain the effect of extension tubes on the magnification of macro lenses (and even non-macro lenses)?
I've seen from other posts that one needs the same length of tube as the lens focal length in order to achieve 1:1. But I have read conflicting information.
The Nikon 55 macro and 105 macro are specified as having 1:2 reproduction. There are two nikon extension tubes: the PN-11 (52.5mm) and PK-13 (27.5mm). I've read that the PK-13 is suggested for the 55 macro and the PN-11 is for the 105 macro, and that this will bring the lenses to 1:1 magnification. So it seems based on this, that if the lens has 1:2 magnification, you only need to have half the focal length in tube length. And for a lens that is 1:3, you'd need 2/3rds the focal length in tube length, etc. and that if I had the full focal length in tube length I would get 2:1 reproduction.
If someone can explain or direct me to a site that explains the math/calculations involved withough going too over one's head, I'd appreciate that.
