Sigma 24-70mm f2.8 DG HSM Experience (WARNING lots of samples)

Hi folks, i've bought a Sigma 24-70mm f2.8 HSM for over a month now and just thought i'd share my experience. Before i bought it, i searched the internet for reviews and found barely any! I'm sure people interested in getting this lens will have the same problem so i'll provide what experience i've had to help with that. The review that convinced me was a chinese review where they compared it to Nikon version and i saw very little difference @ f2.8. Quite frankly, i'm very surprised by the lack of buzz this lens has generated. Anyway, before i start i should mention i use D50 & D300, my lens line-up include: Nikon 28-200mm, 18-70mm, 50mm f1.4 and tokina 12-24mm. I'll be comparing the sigma to those.

Built

On the outside, the lens reminds me of the 18-70mm alot in terms of feel & looks. It is a giantly fat lens, make no mistake about that! The built is a step above the 18-70mm but a step below the tokina 12-24mm. The other thing is, the lens is very heavy, and i can't help think a lens with this amount of weight should have a more solid built. It is a perfect fit on the D300. On D40 & D50 it gets very front heavy, and if you don't hold it by the lens, it feels like it'll break off from the body! I can't imagine this lens being used on a body smaller than D300.Take a look:

Design

Unfortunately, the design isn't of a professional lens. It extends towards the long end, hence may suck in dust over time. However the zoom & focus rings are nicely damped & fluid in use. Unfortunately, it doesn't feature rubber sealing ring around the mount. The petal hood feels really cheap, much worse than tokina's petal-hood and it's actually smaller. Another thing that bothers the hell out of me is the 82mm filter thread. Being in NZ everything's expensive, the only 82mm UV filter my local shop had was NZ$125, so i opted for a stepping ring + 77mm filter instead. To my surprise, when i mounted this combination on FM2 film camera, the corners did NOT vignette! Not sure if FM2 has 100% view though...

AF

One thing you'll notice is the AF pathway is very very short, in fact you can see the entire pathway in the AF window. While this allows fast AF, but i think this may be responsible for the AF problem (that and sigma's QC). Mine has a severe front-focus problem at close distance focus. The dealer tested 3 copies for me all with the same results. D300's AF fine-tune adjustment does help but not at the closest distance (0.38m). This is a serious warning to all potential buyers.

Optic Performance

Now i'm sure this the bit you are all interested in. You can relax, it is easily the best performing lens in my line-up (though that's not hard). It is sharp at all apertures. My benchmark has always been 50mm @f4, and the sigma rivals that at all but f2.8. At f2.8 it's about the same as f2.8 on the 50mm, nothing a little software sharpening can't handle. Above f2.8, everything's so sharp that the prints will give you papercuts! There's also no evidence of vignette except at f2.8 on 24mm, even then it's not very obvious at all. There's also no issue of colour casts and CA is not visible, in fact i can't tell the difference between the sigma and the rest of my nikon lenses. Overall, there's no major weakness that's worth worrying about. It is the only lens in my kit where i don't have to stop down for image quality. Keep in mind the findings only apply to DX format.

I realised number of posts is equal to prestiege around here, so to prove i have at least fundamental basic knowledge of photography & equipments you are invited to check out my pbase. http://www.pbase.com/jeffery . Also, feel free to ask questions about this lens.

Time for some 100% crops (none with UV filter of course!), all on D300 RAW straight conversion with NX2:

1. 70mm f2.8 ISO 3200 this one converted with ACR

100% 1m from subject, focus problem is clear here

2. 70mm f2.8 ISO 3200

100%: No AF problem here!

3. 24mm f2.8 ISO 200

100%: Center

100%: Right

4. 44mm f9 ISO 200

100%: Upper right corner. No CA!

5. 70mm f13 ISO 200

100%: Center

6. 70mm f10 ISO 200

100%: Center