I recently purchased a Zeiss ZE 50mm f/1.4 lens for my Canon 7D DSLR. Very good price, won the auction on eBay, the lens was in excellent condition. I met the buyer at his home and discovered that he was a photography nut like me but anyway that's another story. I am having difficulty focusing with the lens wide open. It gets easier as I go down to around f/2.8 of course. But I've tried taking test shots of stationary objects like a wood fence and even when I'm sure I've nailed the focus through the VF where I can see the grain of the wood in sharp focus, when I chimped it was not even close. I thought there was something wrong with the lens. I've had my 7D for a few years and never had focusing issues this bad. Sometimes I didn't think I've focused properly but then the photo comes up sharp. There are a few occasions when I've been able to nail focus through the VF and in the photo but it's rare. So I know that the lens is capable of being sharp wide open, beautifully sharp. I then switched over to Live View (LV) and tried taking photos that way and I discovered that I can nail focus every single time through the LV. Here's an example of some photos I took of my dog with the lens wide open, close up, razor thin depth of field and my dog was moving the whole time. I still managed to nail focus and the lens is proving itself capable of being sharp wide open: https://www.photographerslounge.org/showthread.php?t=1757&page=142&p=160535#post160535 I don't understand it. It can't be the lens, and it can't be the camera. I thought it might have something to do with the diopter in the VF but I've never had a problem with it before and I can definitely see when the shot is in focus through the VF. Does anybody know what it can be?