All the Quality Control issues are easily found on the internets with Sigma glass mixed in with some happy owners of same:
I bought a 4.5mm f2.8 to use in D700 crop mode last month.
WHAT a HORRIBLE lens!!!
Its my first & last Sigma hands on experience I'll bother with. Luckily B&H took it back granting me with full refund and they paid round trip shipping also to rid me of the late 2007 design sigma.
Thats great Sigma works for you. As a manufacturer of bootleg mount lenses they are dead to me. Have you read of Javier's 4 recent bad experiences with Sigma? They charge him now for "IN" warranty repairs. And this for a guy who bought their AF K Mount 500mm f4 brand new... among other pricey sigmas all new. Me, I like to learn from others mistakes as its easier on my wallet.
I have no regrets adding Canon 70-200mm 2.8 IS. Maybe I was lucky as I have yet to receive a less than stellar image qualty made in japan lens from them. Digital is great as in a few minutes at my favorite local park I can tell if a lens is great or mediocre or crap. I shot about 70 images with the sigma and from close up to infinity was bad, bad, bad..........
Whereas my two nikon made lenses: 14-24mm 2.8 Nikon and 70-300mm VR are tack sharp. I had low expectations on the Nikon Thailand made VR but price made me give it a go. Its exceptional actually ;^) What sold me is all the nikon pro shooter websites that boldly list it as part of their gear. For what the Sigma sells 4.5mm f2.8 for I could have bought two 70-300 VRs . Well thats before Nikon popped the price up. What A Deal it WAS ;^)
The Canon 24-70mm 2.8L has a checkered history. I don't know if canon made slip stream improvements to it over the years but mine has a "UW1012" Date stamp inside mount so its freshly made from Oct 2008 and its exceptional too. Nice thing about Canon over both Nikon and Pentax is Canon stamps a manufacture date code on all the lenses they make. THIS has been a canon thing since Novemeber 1970 to date code all their glass when they launched FD System.
As far as Nikon's 24-70mm 2.8 being the best, I'd guess thats true. I've never read of any single complaint concerning it. But I'm happy I spent $800 less for a Canon version that I'm pleased with. How Cool is that? $800 savings, same focal length covered, I'm Happy. What more can I ask for?
Likely the same scenario with Sigma, you get a good copy or two and Sigma is Great. Me? I'm one for one, sigma sucks and they don't get a second chance due to all the complaints I've read over the years.
Originally posted by kenyee Good reasons, but the 24-70L is an old design that gets spanked pretty hard by the Nikon variant and even by Sigma's new 24-70HSM. The Canon 70-200/2.8 is also spanked pretty badly by Nikon's (if you look at sharpness instead of vignetting). The Canon 70-200/4 is much sharper even if you stop the 2.8 down IIRC. The Nikon gear is much more expensive w/ the big price increase now so your decision probably is better for your wallet now too