Tamron 17-35mm f/2.8-4: A Lens Worth Considering

I am a huge fan of ultra-wide angle lenses. With an ultra wide-angle lens, I can create or manipulate perspective in a photograph with picture elements in foreground and background to give a sense of depth. Its wide angle of view (or coverage) enables a lot of subjects in the frame, especially when there is no room to back away to fill the framing. For scenic photography, this kind of zoom lens is an excellent and important asset.

Tamron SP 17-35mm f/2.8-4 Di LD Aspherical (IF)

Tamron SP 17-35mm f/2.8-4 Di LD Aspherical (IF) AF is an impressive autofocus zoom lens that provides just enough focal range for ultra-wide to wide angle coverage. This zoom is in the SP Tamron line which stands for Super Performance. The Di (Digitally Integrated) designation is the new feature in the lens optimized for digital, while LD is Tamron's designation for Low Dispersion glass, incorporated in the optics design. In other words, this zoom lens is designed to work on both film and digital SLR cameras.

Weighing at just a bit over a pound (14.4 oz.), this zoom lens is well structured with impressive appearance. Its new rubber ribbed zooming and focusing rings are equally appreciative that provide an excellent grip. This new design is far superior to the old plain (and dull) rubber ring. The zoom measures about 3.7 inches when fully extended and collapses to a mere 3.40 inches. It incorporates an Internal Focusing mechanism so that the front barrel does not rotate during zooming or focusing, which further provides a great benefit and convenience in the use of a polarizing filter. The front barrel accepts a 77mm filter ring.

This is a variable aperture zoom lens, which has a bright and wide aperture f/2.8 at 17mm and stops down to f/4 at 35mm focal length. Not bad for an ultra-wide to wide angle zoom. If mounted on a camera in automatic exposure mode, its exposure value will be compensated automatically throughout the focal range. The aperture range runs from f/2.8 to f/22. There is also a marking of the aperture variable shift corresponding to the focal length in front of the aperture ring. The zoom ring has the traditional focal-length markings at 17mm, 20mm, 24mm, 28mm and 35mm.

Mount/Availability/SLR Format

Tamron SP AF 17-35mm f/2.8-4 Di LD Aspherical (IF) is available in Canon, Minolta, Nikon-D and Pentax. It is worth to mention that this zoom lens is compatible with both digital and film SLR cameras.

My review here, however, is based on film SLR camera in Nikon mount. I have tested this lens on both my Nikon F5 body and Nikon F4 body.

Tamron 17-35mm f/2.8-4 Di LD Aspherical (IF) is the standard auto focus (AF) lens in Nikon F mount, and it should therefore be compatible with any Nikon camera body; be it manual or auto focus with aperture indexing. When mounted on a manual focus Nikon camera, focus operation must be done manually via the lens' focus ring.

Field Test, Performance

The Tamron SP 17-35mm f/2.8-4 Di LD Aspherical (IF) yields an excellent handling on my Nikon F5 and F4. It balances quite nicely with Nikon F5. With its tulip shaped hood attached, this zoom lens is quite appealing. Its zoom ring is smooth and well dampened. Its focusing ring is quite smooth but not dampened, though there is enough friction to prevent free sliding. The focus ring has distance scale markings to provide focus information during shooting.

Auto focus response on my Nikon F5 body is very fast, though the AF action is a bit loud than expected (compared to a Silent Wave Motor Nikon lens) but reasonably quiet for a standard AF lens. Manual or auto focus operation is controlled by the camera body (at least in the Nikon mount). In AF operation, the camera body must be set in AF mode. To control the lens manually, the MF switch on the camera body must be dialed to the appropriate setting.

To test the optical quality of this zoom lens, I photograph images using slide film (Fujichrome Velvia 50) with my camera securely mounted on my tripod Gitzo 1340 Mk2 and with a shutter release cable. I photographed the brick wall of a large building in my neighborhood. I set the camera in MF mode. I selected focal lengths in 17mm, 24mm and 35mm, using aperture range from f/2.8 - f/22. However, f/2.8 is only available at 17mm focal length. Therefore, my images at 35mm and 24mm were made between f/4 and f/22. On my Nikon F5, the aperture showed f/3.3 at 24mm setting. I use my 8x Schneider loupe to examine the exposed slide images.

This zoom lens produces admirable picture definition, yielding excellent sharpness, color fidelity and contrast. Sharpness is very consistent throughout the focal range at the center but with a few exceptions in the corners. Overall sharpness at 17mm f/2.8 is average; sharpness decreases gradually from center to corner at 17mm. Stopping down to f/4, corner sharpness at 17mm improved slightly, and improved greatly to optimum performance when stopped down further. Sharpness was very consistent throughout the film plane in aperture range from f/8 to f/16 at this focal length. This is quite good especially when a desired photograph requires stopping down the aperture to obtain sharpness from foreground to background; an excellent focal length to use with aperture at f/11 or f/16.

At 24mm, image sharpness was also consistent between f/5.6 and f/16 aperture range. At wide open, however, sharpness decreases slightly from center to corner. Optimum performance at 24mm seems to be f/8, though images at f/5.6 to f/16 are equally sharp and indistinguishable. At 35mm, image quality is also consistent with the rest of other focal lengths and aperture, but save for optimum performance at f/11.

Severe barrelling distortion was seen at the ultra-wide angle setting, particularly, 17mm and 20mm. At the other end, a pincushion distortion was observed from around 28mm to 35mm. These effects are more pronounced with images that contain straight vertical or horizontal lines. This would impose a real drawback at photographing linear objects, such as buildings in cityscape photography.

There was a clear evidence of light fall-off at wide open at every standard focal length. Light fall-off at 17mm was heavy at wide open f/2.8. Stopping down to f/4 improved a little bit, but still noticeable. By f/5.6 light fall-off seems to disappear.

With a polarizer (Hoya Ultra-Thin 77mm) attached to the front, severe light fall-off at 17mm focal length was observed, even though the overall image was extremely contrasty. I think the effect of the further light fall-off was due to the large field of view that light on either side of the horizon tend to get dimmer than at the central portion.

Flare is very well controlled throughout the focal range. Its hood does not appear to be of much help, but the coatings of the optical elements themselves seem to handle flare nicely. The lens in general will suffer from ghosting only when a bright object (a light source or the sun) appears in the frame.

My slide images of city buildings in St. Paul, Minnesota, taken in late sunny afternoons and dusk, were exceptional and well exposed, sharp with excellent color. This lens produces exceptional contrast on slide film. Images of landscape taken near Indiantown, Florida, during my visit (at my relative's farm) there in August 2005 were quite excellent; great color and contrast with beautiful greens and vegetations. This is a great optics from a third-party lens maker. I have also shot with color negative film (Fujicolor Reala) and obtained similar lush in green colors and other colors in the spectrum. However, its high field distortion let this lens down unexpectedly, particularly on subjects in the same plane or flat field, such as the large brick wall that I had used for my test.

Advantages/Disadvantages in Digital SLR?

The optical flaw in light fall-off and distortion may not be present in images produced by a digital SLR camera. The difference between the size of conventional film and that of digital SLR's CCD or CMOS image sensor could be a strong attribute at eliminating these weak characters in this zoom lens. I may be wrong in this assumption. Since conventional film SLR has image size of 24x36mm and digital SLR (e.g., Nikon D2x) has image size of 23.7x15.7mm, the difference of this 1.5x in focal length could be drastic after all. Images produced with a digital SLR will be images from the central portion of the 24x36mm (film SLR) plane. Therefore, it is plausible to assume that most of these optical flaws are unlikely to register in the field of view that digital SLR's CCD sensor will capture. In that sense, I think this zoom lens would perform very well as a general ultra-wide angle lens. The best way to see this for certain is to mount the lens on a digital SLR camera and run the zoom range from 17mm to 35mm and examine the effects of distortion in the viewfinder.

In addition, the fuzziness in the corners may not show up in the images produced by a digital SLR camera; again, due to the central coverage of the picture frame in the 24x36mm film. However, the disadvantage of this zoom on a digital SLR camera will be the loss of 1.5x factor in focal length. This means that the effective focal lengths of the 17-35mm will be 25.5-52.5mm. I guess it will not be an ultra-wide angle lens after all...

In short, with digital SLR, the advantage of Tamron 17-35mm f/2.8-4 Di LD Aspherical (IF) lies in its improved optical quality. The disadvantage is with its increase in focal lengths.

Conclusion

Tamron SP 17-35mm f/2.8-4 Di LD Aspherical (IF) produces competitive optical quality in terms of color fidelity and contrast. It is quite a sharp lens at smaller aperture. However, its high field curvature, distortion, at extreme wide-angle as well as pincushion at long focal lengths are a real drawback. I was surprised to find a zoom lens in Tamron's SP series to exhibit such optical imperfection. This flaw will be evident in cityscape shots that include linear objects or straight buildings along the edge of the frame, especially those elements in the same plane of focus. If used in landscape, which is perhaps this lens is well suited for, then such distortion may not be apparent. Its close focusing distance at 11.8 inches throughout its focal range is a real plus! To achieve sharp images, this lens must be stopped down significantly. Overall, it is a good zoom lens.

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Specifications: Tamron SP 17-35mm f/2.8-4 Di LD Aspherical (IF)

Model: A05
Lens Construction (Groups/Elements): 11/14
Angle of View: 104 deg. - 63 deg.
Type of Zooming: Rotation
Diaphragm Blade Number: 7
Maximum Aperture: F/2.8-4
Minimum Focus: 0.3m (11.8") (entire zoom range)
Macro Mag. Ratio: 1:5.4 (at 35mm)
Filter Diameter: 77mm
Weight: 440g (14.4oz.)
Diameter x Length: 83.2mm x 86.5mm (3.3in x 3.4in)
Accessory: Tulip shaped lens hood
Mount: Canon, Minolta, Nikon-D, Pentax