Originally posted by kbrede Well there are other reviews out there that speak of the 15 as soft at f/4
Perhaps, but I'd assume they either have a rare defective copy, or else their test methods were flawed - like they failed to focus accurately, or tested sharpness in an out of focus area. Both are pretty common problems with wide angle lenses.
But I'd challenge you to test for yourself in the way I described. Take a head & shoulders shot of a person with the DA15 (you'll be shooting from quite close, of course), carefully focusing on one particular part of the face because DOF will be shallow enough that whole face can't be in focus at once. Then do the same with the other two lenses (from progressively farther away, of course). Then compare the in-focus areas at 100%. I believe your impression of the DA15 will change instantly.
Quote: All I'm asking is for people to list their top performers at wide aperture
Fair enough. Then my answer is that the DA15 absolutely without question is the sharpest lens when shot wide open that I have ever used (a couple of dozen lenses), and its numbers on photozone bear that out.
Second place among lenses I have experience with would be the DA70, followed by the DA40. Here, the numbers don't make those lenses stand out quite so much, so it's mostly a subjective notion.
The M50/1.7 isn't particularly sharp at f/1.7, but by f/2.8 it is as sharp as anything else out there. The M100/2.8 and M28/2.8 are both sharp enough wide open that you'd be a fool to stop down and thus give up shutter speed just to get them a little sharper still. I could (and have!) say essentially the same about *any* lens, but these stand out among the M series lenses I know (28, three different 50's, 100, 120, 135, and 200, plus the 85 by reputation).
The DA*60-250 is, like the DA15, only f/4, and in this focal length range that's an issue for low light shooting, but it's also impressively sharp for that aperture and focal length range. I don't own it, but did have the chance to try it out, and have seen others' images.
I don't own any of the FA Limiteds, but all data and images I've seen suggest they are all incredibly sharp by f/2.8, but noticeably less so at f/2 or beyond. Similarly for the FA35.
Most macro lenses are really sharp wide open.
Basically, most primes that are f/2.8 or so max are sharp enough to use wide open with no hesitation. Most primes that are f/2 or faster are quite a bit softer wide open, but of course, stopped down to f/2.8 become as good as or better than the f/2.8 primes.