Originally posted in another thread, but decided to start a new thread for this.
Just came back... Wow, first comment is that it eats through batteries like nothing. On the D200, I managed to chew through 5 batteries and was on the 6th, with a total of 863 frames through it. Luckily I am shooting through another 2 cams as well so that distributed the load somewhat....else really not enough batteries already. Of course I am someone who pumps the AF often, but this is about 2-3 times more draining in power.
AF is fast and spot on, from what I see on the LCD. Does not hunt much if any under low light. In this "hunting" aspect it is much better than the Tammy. The Tammy would freeze and refuse to lock under real low light, even with flash IR AF assist.
The Sigma is good. Even under 1/2s, 2.8, ISO 1600 conditions, it works without issue for straight over 100 frames. Its much faster than the Tamron and digs much better into lower lighting conditions, really no contest in this area. When I tried the Tamron on another cam, quite a fair bit like 20-30% it refuses to lock, or it takes over 1s to lock after hunting, and often a high % is misfocused.
I remember quite a few times during group phototaking, that the Tamron just refuses to lock (even after power cycling flash/cam etc). Then have to switch over to the 30/1.4 on another body to take, coz you just can't keep the guests waiting. Once I remember very clearly was at Humble House, you know its long table setting there by the windows. At night its candles/flickering Philips LED mood light, the other side got some dimmed halogens shooting at the round pillar, a couple of dimmed halogens at the upper, and then got some alcove at the lower platform, that's about it. Damn the Tammy just die die would not focus even with AF assist coz guests all wearing pretty dark clothes. Focus on faces also dont know why could not lock - maybe the distance had something to do with it as it was a very big table group shot. Just hunt and hunt and then give up. Finally managed to get it locked after quite a while and snapped. WTF NB the thing was totally out of focus! Now before I get blamed, this is with a SB-900 AF assist. Could not really switch to 30/1.4 as that'd mean walking one full round which was not easy as the darn place was packed. Reset both cam and flash even taking out the batteries, cannot make it. In the end really had to spend like 1 minute walking to another table and asking other guests to move away before taking the group shot. Really paiseh, told them equipment failure, but no worries I got real-time backup.
OS works good and within. On a chair's top part as support, I can do 1/2s, 2.8, ISO 1600 clearly at 17mm (effective 25mm) and it would be very sharp. That's over 3 stops of assistance but with aux support.
The lens hood is easily knocked loose. Have to gaffer it tight. Small issue.
Will post again, got another 2 more shoots today tmr.