I've transferred the following Sigma 70-200 related posts by Christian-NRW from the Tamron 70-200/2.8-thread here to give a something to mull over while I'm waiting for my copy of that lens:
To get an impression what kind of dreamy effect the sigma delivers in the near field, I've uploaded a 50% size sample shot from photokina - its clearly visible, even more so at 1:1 100%. This JPG ist OOC, shot was taken around the max. mag. distance of that lens.
If you increase the distance, the glowness is reduced and remains visible mostly around highlights. Nevertheless, it's still there even in the shadows, visible by the overall reduced contrast:
In the far field, the picture looked ok, but lacked the punch that those of the tamron had. There mighht be a small backfocus on this lens as I aimed for the wheel and the brakedisc seems sharper, but overall I wasn't just impressed with the results I got (org. full size file):
Build quality was better at the sigma in terms of surface feeling, it just felt "metal". But as I know how fast this EX finish collects dust and dirt and just gets splotched, I'm not very keen on this finish. However, having a metal outer shell does indeed suggest some kind of reliability.
Here's the Sigma 70mm, notice the plane of focus is on the windscreen wipers although I clearly aimed for the wheels.
Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews
, My Pictures
, My Photography Blog