Using reverse macro rings - help!
I'm thinking about getting a reverse macro ring for my EOS 40D.
My best lenses have a 77mm thread size (EF-S 17-55mm f/2.8, Sigma 70-200mm f/2.8). I also have the canon EF 50mm f/1.8 mkII which has a 52mm thread.
Firstly, can I use any of these lenses reverse mounted as they do not offer control of the aperture independent to the camera body?
Secondly, which lens would offer good magnification with some decent DoF? (not really much point shooting macro if DoF is limited to 1/10th of a millimetre unless I also invest in a slide rail mount for my camera).
and finally... Can the 70-200mm Sigma lens be mounted in reverse safely? It is a heavy lens, I dont want to snap the front filter mount through excessive stress.