Christopher K. Vedeler
After reading all the reviews I wanted to get this lens. I wanted a lens that was fast, both to isolate the subject but mostly for low light. I also wanted a lens that was good for video and would focus well for moving subjects. The lens does a good job, dont get me wrong. It is sharp and it is optically fast. However the deal breaker for me was its inability to reliably focus in low light and its terrible results focusing in video mode. I have a Canon T3i, so perhaps it is the communication from the older body to the lens that resulted in the poor performance. In low light (like candle light) the focus was less than 50/50. Granted this is a torture test of any focusing system, but it performed no better than the kit lens even though it is a full 3 stops faster and the exposure times were shorter everything else being equal. In normal light it focuses much more quiet than any other lens I have, but the speed isnt any better. I did a number of shots using my 10 year old Tamron 18-270 zoom and the Sigma 35mm 1.4. To my disappointment I could barely tell the difference in terms of sharpness. The 35mm was a tiny bit sharper, but not enough to justify $800. It was the video focus that was horrible. Tracking a moving subject the focus would drift and have a very hard time getting back. The kit lens and my 10 year old Tamron performed much better. So why shell out $800 when the $80 kit lens does better? As far as image quality, the Sigma 35mm was slightly better of course, but when it is out of focus for much of the time that doesnt really matter. Based on all the reviews my results may be due to the older camera body, but that is what I have and I had no plans to change anytime soon.