I was looking for a full-frame lens that was relatively fast, but small, and didn't break the bank. Now the 24-85 f/3.5-4.5G kit lens is nice, but at $600 I found it a bit pricey. There are quite a bit of older fast FX lenses out there from Nikon, Tamron, Sigma, and Tokina, but most of them were coming in at $300 or more and weren't quite as small as I was looking for.
|The midget and the beast|
A few days ago I stumbled across the Sigma 28-70mm f/2.8-4 DG. This lens is tiny compared to my Nikon 28-70mm f/2.8D (aka the Beast), and it only loses a stop at the long end. It has a 58mm diameter, it's only 2.5 inches at its longest and weighs in at a whopping 0.5 pounds.
To be honest, I was just about to buy the Nikon 24-85mm f/3.5-5.6 non-VR lens for about $300 used, but when I found this little lens for $70 (almost nothing in FX lens prices) I couldn't pass it up.
I really didn't expect much at this price, but I figured I'd give it a go and sell it later on if it wasn't any good. Well, the lens performed much better than I expected.
SharpnessAt 28mm f/2.8 this lens is good. Center is nice and sharp and the edges are good. Stopped down to f/4 - f/16 and this lens is very sharp. Surprisingly sharp. Sharper than Nikon's 28mm f/2.8D prime. From center to edge it's sharp! (did I mention the lens is sharp?)
At 35, 50, and 70mm wide open the center sharpness is pretty good. Upon stopping down the center gets a little better, but unfortunately the corners do not. Shooting a few frames on my D700 the fuzziness isn't quite as apparent at 1/2 the resolution, but the D600 does show this weakness when viewing at 100%.
This lens does show a small amount of distortion at all lengths. There's a small amount of barrel distortion at 28mm and by 35mm there's some pincushioning being the worst at 70mm. It's not terribly bad, but you might notice it when shooting straight lines or architecture. The good news is that the lens is supported in Adobe Camera Raw and Lightroom 4 for a one-click fix. (My Nikon 28-70mm f/2.8D isn't even supported!)
This lens shows a good amount of vignetting especially wide open at 28-35mm, but disappears when closed down a couple of stops. Again this is a one-click fix in ACR and LR4. Not really a big deal.
Chromatic aberration and lens flare
For Sigma lens the DG designation mean that the lens is designed for digital cameras and that the lens is coated to reduce flare and CA. I don't know what they used to coat the elements in this lens, but try as I might I could barely get any flare even shooting into the sun without a lens hood. This is probably due to the combination of the simple lens design as well as the coating. It's only got 11 elements in 8 groups, less glass for light to bounce around.
|Barely a flare there!|
As far as CA goes, there was almost none to be found as well. I've never seen a cheap lens perform this well. I shot a bunch of high contrast photos and could only see a minuscule amount of fringing. Pretty amazing.
|The CA is under control.|
Build quality and handling
As expected the lens is almost completely polycarbonite, but it has a metal lens mount, feels quite sturdy and doesn't look cheap at all. The zoom ring is a good size and when zooming has a nice fluid feel to it, and it zooms the Nikon way (sometimes lower end lenses zoom the opposite direction, or the Canon way).
The lens is focused by the in-camera focus motor, but it isn't too loud and it focuses surprisingly fast. The bad news is that there is no manual focus override unless you flip the switch on the camera and the even worse news is that there is no internal focus so the focus ring, front element, and lens hood all rotate during focusing. The lens focuses down to about 20" at all focal lengths. It won't get you any real macro shots, but it'll get you decent close-ups at 70mm.
I don't normally include bokeh in my reviews, but this question always pops up at some point so I guess I'll address it now. Whether bokeh is good or not is a pretty subjective view, but I find the out of focus areas when using this lens nice and smooth especially when shot wide open. Better than some fast primes that I've come across.
If you just stepped up to FX and are looking for an inexpensive and reasonably fast zoom lens, or you're a pro looking for a small, fast walk-around lens for your D600, I suggest hunting down one of these Sigma 28-70mm f/2.8-4 DG's. This is definitely an underdog lens that has been overlooked for some time now. This lens has been discontinued by Sigma and there's nothing in their line-up to replace it near this price point.
For snapshots, web viewing, and small prints I think this lens will be a great alternative to the overpriced kit lens and the much larger constant f/2.8 aperture third-party lenses.
For critical work, prints larger than 8X10, or if you're a pixel peeper you're probably going to want something better.
The Sigma 28-70mm f/2.8-4 DG more than delivers the goods considering the $70 price point. I recommend buying from KEH, Adorama, or B&H if you're looking for the lowest price. Searches on eBay show this lens hovering at about the $150 range.
Caution! There's a Sigma 28-70mm f/2.8-4 UC lens. Stay away from that one.
|This review has been Henrietta approved.|