+1 here. 85L is amazingly sharp wide open.
the thing about the Canon fifties is that they are a compromise... af on all, excellent image sharpness when stopped down to 2.8, decent bokeh, but better on the 1.2, but no is.
so what I want is to buy a 1.2 or 1.4 50mm that I can use wide open that is sharp and with a beautiful bokeh... and I really want af and I can do without is, but I'd like that too. sho Canon needs to get off their duffs and make that happen... and I'd happily pay $2000 ish for that lens.
The 50L is not a compromise. Apparently, IS on f/1.2 is technically impossible now. The 50L is designed for bokeh, not for sharpness. Even Zeiss says that you cannot have both (in their "bokeh" document).
I've heard that from multiple sources, but people live the Canon 85's and the 135 L for their sharpness and the bokeh...
and the sigma 35 gets a ton of praise for being sharp wide open... and I know we are comparing apples to oranges, but I just can't seem to accept that it has to be one or the other
Longer lenses are easier to be made sharper. The 85L is sharp enough wide open but not really sharp, with strong PF and reduced contrast. The 135L is long and f/2. The Sigma 35 has really poor bokeh.
My 85IIL is very sharp wide open, my copy seems to be a stellar copy. It's nearly as sharp as my 100mm L IS Macro. Even my 135L isn't as sharp as my 85IIL. It's contrast is fantastic, so I would question the copy which you are using, it must be out of spec. Yes it has Purple fringing in specuatular highlights (no where else) which is easily correctable in LR. The 50 f1.2L is a nice lens but it's sharpness is certainly lacking wide open.
135L = sharp wide open
100L = sharp wide open
85IIL = sharp wide open
50L = not particularly sharp wide open
35L = sharp wide open
24IIL = sharp wide open
Which lens is the odd ball here? Ok, this may be my lens samples..but my 2nd photographer has the same kit and her 100L is a bit sharper than mine, but my 85IIL is sharper than hers...her 50L is a wee bit sharper than mine...but they are both the softest lens in our lens collection by a noticable margin. It's softer than any of our zooms or other primes.
As a L lens, the 50L is well built, it's AF is curiously slower than the 35L. The elements aren't that big. It' AF is certainly accurate, just a little slow to react. My mkI 24-70L is a lot snappier.
The 50L offers great flare handling, great contrast, nice out of focus rendering (bokeh is a term which only references out of focus highlight blobs). But it's sharpness isn't in the same league as my other lenses.