A friend of mine recently asked me what the difference was between the Sigma AF 70-200mm f/2.8 EX HSM APO DG macro and the Nikkor AF-S 70-200mm f/2.8 G IF-ED VR lenses.
I’ve owned and shot with both of these lenses, and aside from having some very different long names, there are some significant differences. First off, I’ll say that they’re both very good and capable lenses.
With that said, the Nikon is the clear winner. VR alone puts it over the edge. I've shot the Nikon at 1/20s at 200mm. Try that with the Sigma. There are so many times when you’ll get the shot because of the VR, and you would’ve missed the shot without it. Advantage Nikon. I can’t stress this enough. Image stabilization, or Vibration Reduction as Nikon calls it, is worth every penny in a zoom lens of this range.
Bear in mind that most DSLR’s these days are crop sensor format, that is to say they are 1.3 (Canon 1D series), 1.5 (most Nikons with the exception of the new D3), or 1.6 (most Canon’s with the exception of the 5D and 1Ds series). Cropped sensors will magnify the hand-holding rules. In other words, the old rule of setting your shutter speed to your lens focal length doesn’t hold true with these sensors. If you want to stay sharp while hand-holding, you’re best to set a higher shutter speed than your lens focal length. For example, when shooting at 50mm, I set my shutter speed to 80s or 60s.
A lot of folks feel that the higher mega pixel sensor adds to this rule yet again. In theory this has something to do with the higher pixel density, and while I’m not a math wizard, my brain can see how this would be. In practice, I have found this to be true, which is all that really matters. Hence, why I would usually set my shutter speed to 80s instead of 60s when shooting with a 50mm lens. Of course, the rules change and you can get away with slower shutter speeds when using flash, but that’s another story.
Back to our lens comparison, the Nikon is also sharper and has better color and contrast than the Sigma. The difference isn't drastic, but it is fairly significant. If you someone who uses teleconverters, you'll appreciate the added resolution you get with the Nikon (and again you’ll appreciate the VR).
Let me go back to what I said at the beginning… both of these lenses are very good and capable lenses. You make excellent photographs with either. The Sigma is significantly cheaper than the Nikon, but the Nikon offers some very significant advantages over the Sigma. You have to decide what your budget is, and if the advantages the Nikon offers are important to you.
I shot with the Sigma, and I made some great photos. I shot with the Nikon, and I made some great photos. Given a choice, I’d take the Nikon. YMMV.
Check out www.photozone.de for the MTF charts and reviews on both the Nikon and the Sigma.