Rangefinder Magazine
November 2005

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First Exposure Stan Sholik
Tamron DI II Digital Lenses

DIGITAL SLR CAMERAS with less than full-frame sensors, referred to as APS-Csized sensors, are here to stay. Tamron is introducing two high-quality but comparatively inexpensive zoom lenses designed for cameras with APS-C-sized sensors. Together, they cover a nearly 20X focal length range, from 11-200mm.

Left: The Tamron 18-200mm f/3.5-6.3 XR DI II LD Aspherical [IF] Macro without lens shade. Right: The Tamron SP AF-11-18mm f/4.5-5.6 DI II LD Aspherical [IF] without lens shade.

These lenses are the SP AF 11-18mm f/4.5- 5.6 Di II LD Aspherical [IF] and the 18-200mm f/3.5-6.3 XR Di II LD Aspherical [IF] Macro. The naming acronyms are: SP (Super Performance), AF (Autofocus), Di II (Digitally-integrated design, version 2), LD (Low-dispersion glass), Aspherical (incorporating aspherical lens elements), IF (Internal Focusing) and XR (eXtra Refractive index glass).

Tamron was one of the first independent manufacturers to introduce a line of lenses optimized for digital imaging photography. For example, by multicoating the rear lens elements, the company was able to minimize internal reflections from the sensor and IR filter, thus increasing contrast and eliminating flare.

Aspherical and low-dispersion glass elements were incorporated to minimize both lateral and axial aberrations, as well as to reduce lens distortions. The design of the new lenses also serves to improve the light path to the sensor surface. Polycarbonate, rather than metal, is used for the outer bodies of the lenses to reduce weight. Initial Tamron Di-series lenses were designed for both film and digital cameras. The latest Di II lenses are designed specifically for APS-Csized sensor cameras. They will cause vignetting if used on full-frame digital SLRs or film cameras.

SP AF 11-18mm f/4.5-
5.6 Di II LD Aspherical
[IF]
One of the early frustrations for photographers working with digital cameras with smaller than full frame sensors was the lack of ultra-wide lenses, and ultra-wide zooms in particular. Easing this frustration somewhat, Nikon has introduced a 12-24mm f/4 for all of its digital cameras, and Canon the 10-22mm f/3.5-4.5, usable only on its S-mount bodies like the EOS Digital Rebel XT and EOS 20D. Also, Konica Minolta recently announced an 11-18mm f/4.5-5.6.

Tamron's 11-18mm lens is available for all APS-sensor Canon, Konica Minolta and Nikon digital cameras. Unlike the ultrawide EF-S Canon lens, this lens will fit all Canon digital SLRs with APS-C-sized sensors.

The 11x zoom range of the Tamron 18-200mm makes it an ideal lens to carry when you only want to carry one lens. At the 18mm setting (left) It is possible to capture wide-angle scenics, while at 200mm (right) you zoom right into the scene.

The lens is lightweight, just over 12 ounces, and compact, less than 3 inches long. It doesn't extend when zooming, nor does the front rotate when focusing, simplifying the use of filters. Filter size is 77mm. Minimum focusing distance is about 10 inches throughout its zoom range, making it possible to take quite dramatic ultra wide-angle photos.

Optically, the lens performs extremely well. Images are uniformly bright from center to edge, with very little fall-off. While I was able to create flare and ghosting by placing 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 practice of multicoating internal lens elements. Multicoating also contributes to the high contrast that the 11-18mm delivers, which is important with an ultra wide-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.

Not only were photos taken with the lens contrasty, they were uniformly sharp, even at maximum aperture. Sharpness drops off slightly at the corners at minimum aperture, which varies from f/22 to f/29. There is some residual red/blue color fringing of high-contrast areas at the very edge of the frame, but it would be easily eliminated with any of the software products out there. I use the Color Aberration Control in the latest Nikon Capture (version 4.3.1).

I found the 18-200mm lens well balanced enough to hand hold at 1/25 second and still get sharp images (here at 150mm focal length at maximum aperture, f/6.3). I did wish for a wider aperture to throw the background further out of focus.

Nikon users will find the focus and zoom controls turn in the same direction as their Nikon lenses. Canon users may find this a bit disconcerting as it is opposite to the 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. Autofocus operation was a little slower and slightly louder than some other lenses, and it isn't possible to touch up the focus using the focusing ring while in autofocus mode. Manual focusing for Nikon and Konica Minolta cameras requires the use of the camera's manual focus switch; while for Canon, the switch is incorporated into the lens.

Although I own an 18mm Nikkor for my film cameras, I don't use it all that often. So I didn't think I would have a lot of use for this lens, which is equivalent to a 16.5-27mm lens on my Nikon digital. Wrong. I found myself removing my 17-35mm lens and reaching for this one very often, not only for the wide field of view, but often to capture the dramatic perspectives that are only possible with an ultra-wide-angle lens. But the more I used it, the more I wished it had a little larger zoom range, like 11-22mm rather than 11-18mm. I found that the comparatively slow maximum aperture is not really that much of an issue, as a lens this wide can be handheld at very slow shutter speeds with excellent results, and it is unlikely that you would want, or even notice, the slightly small depth of field that a wider aperture would yield. One thing I did find a little annoying was the focusing ring, which rotates during autofocusing. This can be distracting if you are holding the lens close to the ring while shooting.

18-200mm f/3.5-6.3 XR Di II LD Aspherical [IF] Macro
I received this lens and the 11- 18mm just prior to a planned vacation on Maui. If there ever comes a time when you need to travel lightly, with one body and one lens, and still want to return with an amazing range of photos, Tamron's 18-200mm would be the lens to take. Available for Canon, Konica Minolta and Nikon like the 11-18mm, it is also available in Pentax mount.

At 14 ounces it is only two ounces heavier than the 11-18mm, and less than an inch longer at its 18mm setting. Extended to 200mm, it grows to nearly six inches. The lens takes 62mm filters on its non-rotating front, but, like the 11-18mm, you will need low-profile screw-in filters like those offered by B+W and Hoya, or the new low-profile or recessed filter holders from Cokin and Lee respectively.

With a zoom range of 11X, it is a lot to expect sterling performance at all focal lengths and apertures. Examining images on the monitor, optical performance seems better at the wider end of the range than the telephoto, with corner sharpness only fair at 200mm and best at f-stops a couple of stops down from the maximum aperture. In the midrange of focal lengths and apertures, images were sharp and contrasty, with no hint of flare or light falloff.

With a lens as wide as the 11-18mm, you often have large areas of sky in the image, which can degrade image quality if the lens isn't well designed. Even with the sun backlighting this catamaran, flare was minimal and image contrast was high.

Like the 11-18mm, this lens will be familiar to Nikon users and seem "backward" to those familiar with Canon lenses. Manual focus is handled in a similar fashion to the 11-18mm also, on the body for Konica Minolta, Nikon and Pentax versions, and on the lens for Canon. And the lens does not permit "touch-up" focusing while in autofocus mode. Autofocus speed is good, especially considering the small minimum apertures involved.

An additional feature found in this lens is a zoom lock switch at the base of the lens. This locks the lens at the 18mm position, preventing the lens barrel from extending while carrying it attached to the body. On the lens I tested, it really didn't seem to be necessary as all of the controls were tight, yet smooth, and the lens barrel didn't extend even with the lens/body combination purposely held with the lens down.

Another feature I particularly enjoyed was the close focusing distance of 18 inches throughout the focusing range. At 200mm this means you can photograph a subject just over three inches long! Perfect for flower and other detail photos while traveling.

However, I did find myself wishing for a larger maximum aperture at times. While traveling you often find interesting subjects against distracting backgrounds, and it would have been nice to be able to throw the background further out of focus, particularly at 200mm. And again, I found it distracting to feel the focusing ring rotate while I was cradling the lens, trying to concentrate on framing the subject.

These minor issues aside, Tamron's 18-200mm is a wonderful lens to mount on your APS-C sensor digital SLR and to rarely remove. It's wide zoom range make it an ideal lens for traveling and its optical performance, particularly at wide to middle focal lengths, make this a great all-around performer.

Street price of the 11-18mm is about $570, including lens hood, and the 18-200mm is about $400, again including lens hood.