Thanks Geoff, Steve & Zane, the MPE-65 is a very competent lens although it has a reputation of being challenging to use. The lens operates from 1:1 to 5:1 and is manual focus only, so you set the magnification you want, say 2:1 and then you sway in or out until the subject is in focus.
The depth of focus is razor thin and I have noticed that if I stop down below F11, I begin to see evidence of diffraction on the finer detail, such as the hairs on an insect’s body.
As you get past 3:1 the viewfinder becomes darker as the field of view shrinks and your subject takes on the proportions of something out of a horror movie!
Cheers
Dennis