Nikon digital SLR cameras all use a sensor that is smaller than 35mm film, but the cameras themselves accept standard 35mm format lenses. The decision by Nikon to use a “cropped” sensor in its digital cameras can be debated ad nauseum as to its merits; depending on their subject, photographers either loved or hated the smaller sensor format.
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The APS-C sensor in Nikon digital SLRs has a “crop factor” of ~1.5X. Wildlife shooters immediately liked the idea of their 200mm lens having the same angle of view as a 300mm lens. While the gains in apparent focal length on telephoto lenses were praised by nature shooters, the downside of this “crop factor” was that now your 17-35mm lens lost its “super-wide” ability and became a pedestrian 26-52mm lens. Many early adopters of digital flocked to their local camera shops to purchase the large (and rather expensive) 14mm Nikkor lens. At least then they had an effective focal length of 21mm; wide enough for some, but not truly “super wide” on a DX format body.
Nikon showed their commitment to digital SLR users in February 2003 when they introduced the 12-24mm f/4.0G DX AF-S Nikkor. For the first time, here was a lens specifically designed to cover the smaller sensor area of the APS-C digital SLRs. Until late 2004, the Nikkor 12-24mm DX lens was pretty much a digital shooter’s only choice for an 18-36mm film equivalent angle of view.
However, 2005 saw new lenses introduced with super-wide focal lengths in the Nikon F-mount from each of the three major third-party lens manufacturers. Enter the Tokina AT-X Pro 12-24mm f/4.0 DX, the Tamron SP 11-18mm f/4.5-5.6 Di II, and the Sigma 10-20mm f/4.0-5.6 EX HSM. Each of these lenses are priced substantially less than the Nikkor 12-24 DX, and appear to offer attractive options for super-wide zooms. We at Nikonians, of course wanted to know how the three challengers stacked up compared to the “venerable” Nikkor.
Nikonians was able to obtain a production-level sample of each of the four lenses from their respective manufacturers. Before we move on, Nikonians wants to thank Nikon USA, Tamron USA, Sigma Corporation of America, and THK Photo Products for loaning us these lenses for our tests. We also appreciate Roberts Distributors, who went out of their way and arranged for us to get the lenses on very short notice.
THE SIGMA 12-24mm LENS
Some may ask why the Sigma 12-24mm was not included in this test. All reports are that the Sigma is a very fine lens, and it has the virtue of working on 35mm bodies at all focal lengths. If that’s important to you, the Sigma 12-24mm is the clear choice. If you’re looking for a DX format super-wide lens that will let you easily use filters (the primary drawback of the Sigma), one of the four in this review is currently the only choice.
So, with a camera bag full of super-wides, a Nikon D2x and a Nikon D70, the three of us set out to put these lenses through their paces. We tested these lenses in real-world conditions; anyone who wants to dwell on MTF charts can look them up from the manufacturer’s own websites. We approached this review from the perspective of the Nikonian who is looking to get back their wide angle of view that they were used to with an 18-35mm or 17-35mm lens on their film body. Chances are, if you want a lens this wide, you’re either shooting landscapes or photojournalism-style photography.
To level the playing field between cameras, we shot our test images in JPEG mode with sharpening set to medium-high in the camera. Both cameras were tripod mounted and set to ISO 200, and we used aperture-priority matrix metering. We also shot some images in RAW to evaluate post-processing techniques for removing vignetting and chromatic aberration. We looked at sample images at 12mm, 18mm, and (where available) 24mm. For the Sigma 10-20mm, we also looked at images made at 20mm and 10mm.
We shot a series of images with each lens at a range of f-stops; from wide-open to f/22. We repeated the image series at each focal length for each lens. The test shots were then subjectively evaluated for center and edge sharpness, chromatic aberration, and light fall-off (vignetting). We also judged the build and handling characteristics of each lens.
So here, alphabetically, are our individual reviews of each of these super-wide lenses, followed by our summary and conclusions..