I have the lens times subjected to a test as I have photographed a large calendar with Linen of 1m size, here are my results:
- From 17-35mm strong distortions barrel shape but from 35-70 mm almost distortion (for the 2nd star).
- Compared with the Sony the results are approximately 1/2 to a stop level too dark.
- The Sigma seems a bit to focus precise will, probably due to the slightly higher light intensity. But needs a little longer as the transmission in the lens is probably translated longer.
- The worst part, however, is the edge blur. If I have to stop down at least 8 panel. To get at 17mm sharp edges, I benötge no intensity of 2.8. Although the Sony, however, has only just begun with an aperture of 3.5 at is there but on the edge already relatively sharply and at an aperture stage more knackscharf.
- The Sigma is to use really only in the range of 35-70mm. But there are other and better alternatives.
But I have decided to keep me now my SONY and give the Sigma back.