Generally speaking, the Canon EF 100mmis a great lens. The bokeh is fine. The lens is pretty fast. f/2.8 to f/22 is useful as a creative range. The optics are sharp and the all-time focusing is a boon. So what’s not to like? Well, here’s the thing. The Canon EOS50D, which I use, has the ability to use the viewfinder in “live preview” mode, and when doing so, will allow you to zoom in on your focus point (or anywhere else, but that’s irrelevant to my point here) such that you can see extremely fine detail. At which point you can manually focus the lens so that it is exactly right. Marvelous, right?
It would be. But the lens has some mechanical backlash problems. Let me explain backlash; if you’re not familiar with it, it takes a bit of describing.
Read the rest of this entry »