Erik_L wrote in post #13646647
I was having the biggest problem at a recent event - I was tasked with doing "stand and repeat" for about an hour doing pictures of people in front of a sponsor backdrop - I can't post any of the pics.... Even at f/2 and a pretty good distance, it would consistently miss focus - I manually put the point over someone's face, would not recompose, and still had problems. AF assist from my 580 was enabled but didn't seem to help. the light was tungsten lights in the room. I was getting good and pissed.
^^All with the 35L
As for spotting focus shifts - the Ec-S screen is in the mail

With the current screen, I can't see a 3" focus shift in the viewfinder.
Here's another great example of my "poor technique"
http://www.flickr.com …5/sets/72157627679630804/
of the maybe 600 photos I took, I think 3 had missed focus. 35L and Sigma 85 f/1.4 all day. I'm pretty picky about what's "sharp" I've seen a lot of "professional" photos I would have thrown out for being not well enough in-focus.
Well, looking at the full-size image, maybe the focus went a bit back into here hair, it's hard to tell, because, well, even viewing at 100% her face is maybe slightly soft...
So, let's get this straight -- you are saying that out of 600 shots, this is one example of three that "missed"? Hmm, one shot out of 200 that at worst is a bit off...to me, that would be "all in a day's work", having 199 out of 200 shots that nailed it and the one that was still usable...