Image magnification ratios and exposure factors.-(50mm standard lens)
from Lens Front
to Subject (cm)
Reviewed by 1 customers
I had been using a Canon 25 Extension Tube with my 85mm lens for macro shots. I needed just a little bit more magnification to bring the subjects a bit closer. The "Kenko DG Auto Extension Tube 12 for the Canon EOS AF Mount" did just what I was looking for in combination with the 25. I rarely use the auto focus function as the DOF is so short that the AF is a bit difficult. I find it much easier to use the manual focus for macro. I can use the 25 and 12 together without degradation because extension tubes have no glass. Your photo quality is only as good as your main lens. I also use the extension tubes for macro with my 400mm telephoto lens. I can stay 6 to 8 feet away from a subject and still get a nice macro.