But, actually, I missed the point about the shorter MFD of 20 cm that I just read in the description, vs. 38 cm as stated in the Canon specifications
. Thanks for pointing that out!
Let's think about the practical implications. An MFD of 20 cm, with the Canon flange-focal distance of 4.4 cm and a lens that when extended to 70 mm focal length is 12 cm long (DPR's spec is a little longer, I subtracted for the part of the mount that extends behind the flange). So the working distance of the bare lens is ~3.6 cm, and if you put on a Canon EF 25 II extension tube (which is actually 27mm long), your working distance is 0.9 cm
, i.e. to get that almost 1:1 magnification, your subject is less than a finger-width from the front element
. Yikes! H-IS for longer exposure or not, with the apparent light loss at high reproduction ratios, it's going to be pretty hard to use this lens for macro.