First Exposure: Tamron SP AF 10–24mm f/3.5–f/4.5 Di II LD Aspherical [IF] Lens

One of the earliest criticisms of digital SLRs with APS-C (smaller than full-frame sensors) was the lack of lenses capable of delivering an ultrawide-angle field of view. Not only photojournalists, but fashion and wedding photographers also use the unique capabilities of ultrawide-angle (UWA) lenses to create a unique point of view by placing the subject in its environment rather than isolating the subject from its environment. And of course UWA lenses are essential tools for landscape, architectural and interior specialists.

It didn’t take camera firms, as well as third party lens manufacturers, long to respond to this need, not only with fixed focal length UWA lenses upgraded for digital sensors, but also with UWA zoom lenses. Until now, the UWA zooms from independent lens manufacturers available for a variety of camera systems were limited to a maximum zoom ratio of 2X. Tamron has broken the 2X zoom ratio ceiling with its SP AF 10–24mm f/3.5–4.5 Di II LD Aspherical [IF] lens, currently available for Nikon APS-C bodies as well as Canon. Pentax- and Sony-mount camera users will need to wait a bit longer. To explain the naming acronyms, which seem to be getting out of hand from many manufacturers: SP (Super Performance), AF (AutoFocus), Di II (Digitally-integrated design, version 2), LD (Low-Dispersion glass), Aspherical (incorporating aspherical lens elements), and IF (Internal Focusing).

The lens is just less than 3.5 inches long at the 14mm position and the length increases slightly at both the 10mm and 24mm positions. It is light, weighing just over 14 ounces, thanks to the use of polycarbonate rather than metal for the lens body. The lens is finished in matte black that is indistinguishable from the finish on the latest Nikkors. The zoom and focusing rings are finished in ribbed rubber and different enough in size and feel that there is no question which one you are holding. The ribbed rubber provides an excellent grip, but tends to collect dust and dirt due to its stickiness.

This is a good time to mention that Nikon users will probably be more comfortable, at least initially, with this lens than Canon users. The focus and zoom rings turn in the same direction as those on Nikon lenses. Unless things change on the Canon-mount lens, Canon users may find this a bit disconcerting, as it is the opposite direction to which they are accustomed. Both controls work very smoothly, another indication of the care Tamron has put into the design and manufacturing of this lens.

Although the Tamron lens incorporates a motor, autofocus operation is a little slower and somewhat louder than my Nikkor lenses with built-in motors. And it is not possible to touch up the focus using the focusing ring while in autofocus mode, as is possible with Nikon lenses. Tamron warns that serious damage could result. Manual focusing for Nikon cameras requires the use of the camera’s manual focus switch as well as the AF/MF switch incorporated into the lens.

Lenses with a fixed (constant) maximum aperture are prized by professionals. The Tamron 10–24mm varies from f/3.5–f/4.5, making it a little faster at the wide end and a little slower at the long end than other UWA zooms. If the focal length markings are accurate, the f/4 aperture kicks in at about 13mm and f/4.5 at just over 18mm. If this were a lens for a film camera, that would probably be a deal breaker for me, since I’d be shooting transparency film with manual exposure. But capturing digitally, it just means I have to do a little exposure tweak on some images, which is no big deal. Minimum aperture is f/21 at 10mm and f/22 from 12mm–24mm.

Filter size is 77mm, but you will need ultra thin filters on this lens. My normal thickness filters caused obvious vignetting. The front of the lens doesn’t rotate during focusing, simplifying the use of filters such as (thin) polarizers. A flower petal lens hood is included with the lens at no additional cost as it is with some lens makers.

UWA lenses are great in landscape photography for capturing a wide field of view, but to creatively use their ability to exaggerate perspective, close focusing is required. The 10–24mm delivers on that count, with a minimum focusing distance of 9.5 inches throughout its zoom range. At 24mm this amounts to a magnification of 1:5. At 10mm you can focus on a fallen cactus and show the surrounding desert and the mountains in the background. Dramatic ultrawide-angle photos are easily possible with this lens.

Tamron seems to have pulled out all stops in the optical design of the 10–24mm. Twelve lens elements are present in nine groups. The front element is a single high-precision, large-aperture glass-molded aspherical lens element and three hybrid aspherical elements are incorporated to minimize spherical aberration, coma and distortion. In addition, the lens uses a pair of low dispersion (the ‘LD’ acronym) glass elements to compensate for on-axis and lateral chromatic aberrations. Multiple layer coatings are used on many air/glass surfaces including the exposed side of the rear element. They are also used on the cemented surfaces of lenses within groups to minimize image degradation caused by reflection of light rays entering the lens and those reflecting off the image sensor.

Evaluating the optical performance of any single lens is a slippery slope. There’s no way to know if the lens in my hands is typical of the run of Tamron 10–24mm lenses. If it is, then Tamron has succeeded very well with its complex design and manufacturing, once you stop down from maximum aperture to f/8. Center as well as edge sharpness improves visibly from maximum aperture to f/8 at all focal lengths and remains very good from there on. The “perfect storm” of softness occurs at 10mm, f/3.5 and minimum focusing distance, resulting in obviously soft images. Under the same conditions, but using an aperture of f/8, the captures look significantly better.

While I was never bothered by chromatic aberration, red/blue fringing is quite evident at all times at the edges of high contrast areas. This is easily eliminated using the appropriate slider found in most post-production imaging software.

Also an issue that requires post-production help is the barrel distortion that is also present at all focal lengths, though worse at the shorter the focal length. This is not the lens you’ll want to use to photograph brick buildings straight on without post-production help. As with red/blue fringing, most imaging programs also have a lens distortion correction tool to deal with the problem. Realistically, it is unlikely that you will notice the barrel distortion in your images. I didn’t bother to apply any distortion correction to any images shown here.

I did find that images are uniformly bright from center to edge, with very little vignetting. While I was able to create flare and ghosting by pacing the sun just outside of the field of view, under normal shooting conditions, even with the sun or other light sources in the field of view, flare and ghosting are well controlled by Tamron’s multicoating of internal lens elements. Multicoating also contributes to the high contrast that the lens delivers, which is important with an ultrawide-angle lens, since there are few subjects you can shoot that won’t have large areas of sky or bright light sources that could potentially degrade image contrast.

Ultrawide-angle lenses aren’t for everyone, but with the unique field of view opportunities they open up, they can be valuable tools in the right circumstances and in the right hands. At its widest 10mm focal length, the lens is the widest available for APS-C sensors. At its longest 24mm focal length, it segues nicely to your 24-to-whatever mm zoom without creating a gap or overlap of focal lengths.

Street price of the lens is about $500, including lens hood. For more information go to www.tamron.com.

Stan Sholik is a contributing writer for NewsWatch Feature Service. He is also a commercial photographer with 30 years of studio and location experience.