Summary: This lens in THEORY is amazing. But in practice its just didn't live up. The lens had focus issues. It wasn't me. I'm no noob to the world of cameras and autofocus too. My other lenses focus just fine and I'm not a Nikon fan boy, I usually look for the best lens at the best price. Ended up returning the lens.
Summary: This is one of my (no scratch - my only) favorite lens at this time; Well, until I pick up the sigma 30 / 35 mm ART F 1.4 that is. This lens is a keeper. Solid focus at f 2 - 2.5 where sharpness is king. Lower f stops brings out all that super sliky bokeh that you love. I will say this, speed performance can be iffy at times as I have found that sometimes the lens can get confuse when you use Auto Focus. I am usually in manual these days so it doesn't affect me as much.
Summary: This lens really lets you do 2 great things! 1: Great Bokeh! You can really isolate your subject from the back ground when at f/1.4, your depth of field is so shallow, I have had a girls nose perfectly focused and her eyes out of focus, lol. just make sure you focus on your area of interest when at f/1.4, step it down to f/2 and you are golden for isolating people Here is a shot where I walked up to the model to push this lens: [...
Summary: I've shot with a bunch of different 50mm, mostly Nikon. I actually sold my Nikon 50mm 1.4G and replaced it with this and I'm so glad i did. The way this lens renders bokeh is different than the Nikon lens. It gives a nice character to the picture. The AF on this lens is hands down faster then the Nikon 50mm 1.4g. At the same time the Sigma is bigger, heaver, and the glass is more exposed, BUT it is completely worth it.
Summary: I love this lens. There is a lot of technical review of this lens, so I'm not going to get into that. I'm just going to speak to the size. Frankly, I expected something huge and heavy based on others reviews, but really this lens is well sized and a good weight in my opinion. It's of course much larger than the Nikon 1.8 and 1.4 50mm lenses, but I feel the size and weight of the Sigma are a perfect compliment to my D7100 body weight and it all balances well together.
Summary: I had read about the possibility of focussing problems with this lens so I ordered two and prepared to test on my 60D. Both lenses had significant front focussing problems from 1.4 to 2.8 after that everything was fine. Tested using two chess pieces and focussing on the rear piece. Distance between the two was about 2cm and the focus was unfortunately always on the front piece instead of the rear one. I sent both lenses back and waited for the replacement order.