I can't believe I've waited so long to buy this lens. I rented the Canon 15mm fisheye before, and the Sigma performs exactly the same and is well worth the money. I primarily shoot nightlife and special events professionally, and in a crowded club, this is the perfect lens. Not only is it great for capturing subjects with minimal distortion (it takes some practice with distancing to get it right) but the wide angle captures all the activity around giving life to an otherwise normal nightlife shot. It also makes the venues look much larger than they are, which my clients love. I just worked a rather large event in LA for NYE 2014, and used this lens as my primary - the results are amazing and probably some of the best work I've produced for a nightlife event. I must admit I was a little hesitant to get anything other than Canon due to concerns regarding quality, but I'm very happy with the Sigma and would recommend it to anyone. FYI - although it doesn't mention it, the lens comes with a lens case - no need to buy an additional one like I thought I had to. ;)

Before going 100% digital I shot Nikon F5 35mm film camera. I had a full complement of Nikkors including the 16mm 2.8 fisheye. When I went digital it was the APS-C cropped sensor that made the fisheye pretty much useless. So I sold it. Now, I am once more full frame with a D600 and D610. I wanted another fisheye and since it won't get the hard use of my other lenses and based on the B&H sales person's recommendation, I went with the Sigma which is considerably less expensive. As has been my long-time experience with B&H, the sales person was correct that the images are comparable to the Nikon. I am not suggesting that the Nikon and Sigma would be equal on an optical test bench. I am saying that in real-world photography, I don't see much of a difference. The Sigma is sharp, fast, and has the distortion you would expect of a fisheye lens. Some of that is mitigated by keeping the horizon centered in the frame. It is a fun lens and is surprisingly handy for candids in, say, a crowded space.

im using this lens for landscape photography. get very sharp and color pictures .

I purchased this lens to use it specifically for skateboardng photos and video. The fisheye effect it provides is hard to reach with a different lens range. And it allows you to get really close to the subject, without having any part of the subject's body out from the composition.

Very sharp... Interesting bokeh at 2.8

This is a small, lightweight lens with great image quality. I was just as satisfied with the results at f/2.8 as I was at f/16. It's a bit slow to focus and that slowness is made a bit more apparent by the noise of the focus motor, but focus speed is probably not critical in the more common uses for this lens.

This gives me the look I wanted , The lens is sharp and a great value.

I enjoy the look of a fisheye periodically but wasn't sure I wanted to pay the added cost of the nikon 16mm fisheye, especially as old as the design is. I don't normally use third party lenses but am quite pleased with this sigma fisheye. It is quite sharp and focuses accurately and quickly. The build is solid and overall it is a very nice product. This is useful for a different perspective on landscapes as well as interiors. It even works for a different angle on portraits. Obviously this is somewhat of a novelty lens but I am very impressed so far.

I am a professional wedding and stock photographer (architecture and travel) and bought this lens to use with my Canon 5D Mark III. I used to have a Tokina 10-17mm Fisheye, but the Tokina is soft on the borders when used with a Full Frame camera (very soft). The Sigma 15mm is tack sharp in the center and very good on the borders. I read in the reviews when I was searching for a fisheye designed for full frame cameras that this Sigma 15mm has a slow autofocus. Well, I do not agree. The autofocus is fast enough for the kind of job I get (weddings and architecture). Maybe for sports, the autofocus will not be up to the challenge. The construction is very good except for the lens cap. Actually, the cap has two stages: a cylinder and the lid itself. The set is too loose and falls off easily. I strap them to the lens via a couple of rubber bands otherwise they can easily go off the lens in the camera bag. The imagens produced by this lens is top notch. Canon has a very expensive new fisheye lens (Canon 8-15mm F/2.8 Fisheye) and an old version (Canon 15mm F/2.8 Fisheye). The old version is sold for the same prince as a brand new Sigma 15mm F/2.8 fisheye and the new version is far too much expensive. I do not see any point in buying the canon's fisheye lenses. As I said before, the new Canon 8-15mm F/2.8 Fisheye lens is far too much expensive and the second one is only found used and selling for the price of a brand new Sigma! (nonsense)... The Sigma 15mm fisheye is a F/2.8 fixed aperture lens what is a big plus when photographing weddings in a very low light reception place. The sigma has also less chromatic aberration compared to the Tokina I used to have before...I recommend this lens.

i use it in in wedding, land scape etc.it's on my bag where ever o go love...love....love