Summary: Excellent lens.Great for using with fireworks and doing Panoramas.I am amazed at the field of vision and how sharp and crisp the photos were. This lens goes with my travelling kit. Looking forward to using on my next trip overseas.
Finally found the wide angle lens I've been looking for!
Dennis Vogelsang, Amazon
16 December 2012
Summary: Just bought this lens a couple of days ago. Here is my review: The Sigma 12-24mm f/4.5-5.6 DG EX is an amazing lens! In my opinion, better than the Tokina 11-16mm f/2.8 and Canon's EF 17-40mm f/4L lens, which I've both owned and sold due to moving to full frame (hence selling the Tokina) and not liking the focal range of the Canon (I find it too close to my Canon EF 24-105mm f/4L lens).
Conclusion: I don't understand why people pick up a lens second-hand, find it doesn't perform very well and then denigrate it without checking to see if it is faulty or if it was abused by the last owner. Why was it sold and why was it so cheap? Do they never ask these questions? No. They run off at the mouth and give a perfectly good product a rating of one because they bought a wrong 'un. Better to not rate it at all, huh? How about sending it in for service? Nope.
Pros: Range, build quality, image quality
Cons: Can't use a polarizing filter at the wide setting.
Summary: I think this lens, and probably most Sigma lenses, is maligned by many people because Sigma is known for poor quality control. Well, apparently I got lucky. I cannot believe how well this lens works on a 5D. People, if you've got a full-frame camera and you need to go ultrawide, THIS IS THE LENS YOU NEED. Mine focuses accurately and quietly, and I can't be happier! Furthermore, it's SHARP, and I mean SHARP, on a Canon 5D.