Focus tests just taken. All shots at same distance and focus point (no refocusing between shots).
DA* 55m f/1.4 at f/1.4, DA* 55m f/1.4 at f/2, DA* 55m f/1.4 at f/2.8
I feel the lens is noticeably soft
in a focus test at f/1.4, but very sharp at f/2. But here are examples of real-world shots courtesy of my coworker sitting still for a minute:
DA* 55m f/1.4 at f/1.4
DA* 55m f/1.4 at f/2.8
I feel these are harder to find fault with at f/1.4, in fact the shot at f/2.8 is slightly soft because it was 1/20th of a second handheld whereas the f/1.4 is 2 full stops faster and therefore more usable. The DOF is really shallow at f/1.4, providing nice separation if you get the right portion of the subject in focus. It's sharp at f/2 and you can cut yourself on it from 2.8, I didn't see any difference between f2.8 and f11 in an earlier test.
For comparison's sake, here's the DA 50mm f/1.8:
DA 50m f/1.8 at f/1.8, DA 50m f/1.8 at f/2.0, DA 50m f/1.8 at f/2.8
The 50mm is a great lens for the money but it remains soft at f2.8.
I just bought my DA* 55, got it Monday, and have been very pleased with it. I tend to regret big purchases but have had zero cause to regret this lens, even though it struggles a bit with autofocus in low light and in high contrast situations.
For myself, I think an 85mm is too long for good portrait work, I already have to stand a long way away from my subject to get full body with the 55mm, and on a crop frame the 55mm is (roughly) the equivalent of 85mm full frame. That said, i haven't used the 85 1.4. It would be interesting to see focus test results at 1.4 with it, but I suspect they would be at least similar to these -- wide open most lenses just aren't as sharp as they are stopped down a bit.
Hope this helps.