05Xrunner wrote in post #15613123
so your 15-85 helps you get a static shot at a slow shutter speed in same light with IS..but thats not going to do squat when the subject is moving and you need the shutter speed of the faster 1.4 lens. Also the 15-85 is not going to give you subject isolation like the 30mm will with its 1.4
Of course not. All I was trying to indicate is that as a result of the decentering I could get a sharper image in relatively low light hand held at 1/6 second with the 15-85.
However, all that's changed. In the last 30 minutes a new Sigma 30mm arrived on my door step. I first took a couple of shots and it looked terrific. Very sharp in the center even at f/1.4. I then tested for decentering using a couple of tools. The centering seems dead on at f/1.4. I also tested up to f5.6.
My first opinion of this replacement lens is that its everything the previous one was not. Very sharp in the middle and moderately sharp at the edges wide open. Stopped down to 2.8, depending on the ambient lighting and the distance to the subject, my new copy seems about as sharp across the frame as my 15-85 stopped down. This is preliminary, and I reserve the right to change my opinion. I'll post examples later. So far very happy!
The first Sigma 30mm is going back to B&H on Monday.