Summary: This is the only "off" brand lens I own. I borrowed one a while back from a friend because I wanted a true wide angle macro. I did a very thorough test of this lens and it is as good as my better Nikons in macro mode. Not surprisingly the color is different but a grey balance and its good to go. I love this lens and the quality it provides as a macro.
Summary: Moving from crop sensor to full frame and aren't looking to refinance your home in order to afford a wide angle lense at a wide aperture? Than this is the lens for you. At a professional 77mm, this lens fits all my (rather expensive) filters. The only other option is the 20mm 1.8 (a much better lens, admittedly) however, it only comes in 82mm, a deal breaker.
Sigma 24mm f/1.8 EX DG Aspherical Macro review by jedy
5 April 2013
Summary: I'm using this with a Canon 600D/Rebel T3i. For the price, this lens is a true bargain. It offers wide angle (or wide-normal on crop) and macro (not true 1:1) which is a welcome bonus. The bokeh is pleasing enough and shallow depth of field great for arty shots. On the downside, the front element extends when focusing meaning you get quite extreme lens breathing.
Pros: Price, macro, pleasing bokeh, 1.8 apperture
Cons: focus ring travel, lens breathing, no HSM, CA.
Summary: There is no other 24mm wide angle large aperture lens out there that doesnt cost you...your marriage. Image quality is good at least my copy. You'd better pray to get a good copy. Focus is a bit slow only in low light condition. Macro is great. You can do some really tight pet shoot. It's sold very cheap used. At that price it is no doubt a great product for the money. Get it if you need 24 but can't afford the 1.4. The extra 1100 dollar is huge.
Summary: I bought this lens for no special reason other than because i wanted a prime lens with a bit of wide angle view. I didn't use it that much for the first year. But when i started shooting Stock Photography...this became my go-to lens! It's fast, tack sharp and give you a great control when shooting different scenes.It doesn't blow your subject out of proportion like a real wide angle lens.
Summary: I can not imagine that it's possible to create better lenses then this one with the same 24mm. Extremely sharp and accurate. F lock and auto/manual switch of ring are awesome features. Thanks a lot !
Summary: I was hesitant to get this lens for my 5D MKII for two reasons, the first being that I've had 4 copies of the Sigma 50mm 1.4 and only 1 was a keeper, with the others all having the infamous focusing issues to varying degrees (and now I've switched back to the Canon 50mm 1.4 and couldn't be happier; it just works.