Summary: Excellent Lens

Comment: I bought this lens because I like to shoot photos at airshows. Shooting small fast moving planes at great distances is a challenge. This lens makes it much easier. The Optical stabilization is perfect. Sigma goes farther than Nikon in their stabilization. I have used Nikon VR lenses and did not get the greatest results when panning. Sigma solved that problem. The lens is sharp at both ends of the zoom, which is impressive. The focus is incredibly fast. Mated with my Nikon D300, this lens is producing amazing images.

Summary: great lens

Comment: This is a great lens. I admit its hard to use sometimes because of it's size but that's because I am always handheld with it. I have gotten some great shots holding it though. I would reccomend it to anyone. I use it on my nikon D80 and it's really cool. The Nikon equivalents are soooo expensive and I bet you cant' tell any difference. Buy it!

Summary: Be aware that Sigma 150-500 does not have 3 year extended warranty and it is impossible to register for the product

Comment: I bought this item and tried to register it as written on the warranty card. There is no place to register on www.sigma-photo.com and on the global Sigma site and there is no extended warranty. The Sigma's rep confirmed this. It is a big disappointment since I thought that it includes 3 year extended warranty as is advertised on Sigma 10-20mm f/4-5.6 EX DC HSM Lens for Nikon Digital SLR Cameras:

"Important Warranty Information: This new product includes a 1-year warranty plus 3-year extended warranty with registration. Once registered, the protection is valid for a period of 4 years from the original date of purchase. See included warranty card for details."

I was thinking of buying Sigma 10-20 mm but now am not sure since Sigma reduced warranty for its lenses. This means only one thing: they are not sure in the quality of their products.

10/22/08: After further conversation with the rep I found out that only EX lenses (Sigma 10-20 is one of them) have 3 year extended warranty. Other lenses such as 150-500, 120-400 have only one year. And it is true: you cannot register on Sigma site, so keep your warranty card!

Summary: Awesome Lens

Comment: I resently purchased this lens after reading a very postive review in Popular Photogaphy Magazine. I have been using it extensively for coverage of high school soccer, hockey,and football, and it has performed flawlessly. It has exceed all expectations and has become my favorite lens for shooting daytime sports. Each and every photo I've taken is tack sharp at all focal lengths. There is no perfect lens on the market today, but this one comes pretty darn close! I would highly recommend this lens to anyone involved in sports or nature photography.

Summary: Very sharp if you can get it to focus properly

Comment: I tried this lens out on a Nikon D700 but sent it back due to back and front focus issues throughout the entire focal range of the lens. The D700's AF Tune feature cannot compensate for both front and back focus at the same time so eliminating one only increased the other.

I will add that when the lens was properly focusing it was very sharp wide open and extremely sharp stopped down one stop.

I don't know if I just got a bad sample of the lens, or if Amazon's poor packaging played a part in the lens' issues. The lens was shipped in a box with inadequate padding to protect all sides of the lens' box. The Sigma lens is packed loose in its nylon carrying case, with no additional in-box padding, so there was nothing to keep the lens from bouncing around during transit.