I just read 50 1.4 review and completely have no idea why NOONE mentions about its huge problems with AF. I have a 5D3 and tested 7(yes-seven) samples of 50 1.4. First one I just sold after servicing as I thought it's a lens problem or camera, next one I serviced 3 times with my camera. Thought it might be something with calibration, adjustments etc. Then I checked with my local shop another samples so...every 50 1.4 has the same issue!!
Why nobody check this lens AF with different distance??? it has HUGE focusshift at close distance and it is almost unuseble in some circumstances when stopped down. To be more detailed:
When focusing at close distance ie. up to 1m ie. 60 or 70 cm (if u set AFMA perfectly @ F1.4) the lens hits the target Checked and adjusted with LensCal. Now check the lens at f3.5 or f4.0 at the same close distance. No way u achieve the proper focus. It far away for your desired focus point. Backfocus is really bad. Point "0" is completely out of focus and blurred, the sharpest point is "2" or "3" at the scale.
The lens is completely unusable stopped down at close distance, 1.4 is very soft therefore there is now way the get really sharp photos or desired details. Lens spec. mentions 0,45m as minimum focus distance. Checked it with ie. f3,5 and watch where is focus, sharpness and where is the whole DOF-behind the focus point!
Now do the same with LV-perfect focus, razor sharp, completely different DOF position.
Another problem is focusing in incadescent light-try this with this lens-results are really different from daylight.
Tested a lot of 50 1.4 (seven) from diffrent sources, not is the same time, and all have the same problem. Why nobody mention about such a issue???