This is my second Sigma lens (the other one I own is 10-20mm), and I am pleased with the quality of image it helps produce, enough that I'd buy it again if I have to.
I wanted a lens that I can use for all kinds of situations when I'm outdoors shooting nature, shooting portraits on assignment or capturing our family life. After three months of use, I am very satisfied with the results and here is why.
- The lens is very sharp at just about any aperture. I'm pleased with all the details I see in my images when I'm shooting buildings or other objects, as well as when I'm shooting people. In fact, I am sometimes amazed at the sharpness I get.
- I love the fact that being f/2.8 lens, I can use it in dark situations. Now I am not forced to pull out my 50mm f/1.8 every time and this lens gives me another option for low light photography, with more of a range of zoom.
- It's not too bulky and well built.
- AF works very well and faster than my Nikon 50mm f/1.8
- It handles color very well.
Now a few cons.
- The images are somewhat soft when you're shooting at f/2.8. However, I knew that was the case from other reviews, and it's fine by me. If I'm after sharpness, I can always apply little extra of it in post processing. I didn't want to pay few more hundred bucks for Nikon's version of this lens just to get a bit more of sharpness at f/2.8.
- It uses 82 diameter, which forced me to buy new filter adopter ring and expensive polarizer.
- It's probably not the sexiest looking lens out there, but hey, once again, you get what you pay for with Sigma
- Sigma really needs to work on the design of their caps and screw caps on the back of the lens. It takes longer for me to put these on when compared with Nikon lenses and sometimes it's a pain when you're outdoors in the dark.
Overall, I'm very happy with this purchase, and I now shoot 80% of the time with this lens. If you're on a tight budget during these uncertain economic times, this lens may be a good idea.