Tamron’s AF18-200mm F/3.5-6.3 XR Di II Lens;

Tamron's AF18-200mm F/3.5-6.3 lens is part of their digitally integrated (Di II) lens series that's designed for digital SLRs and is not recommended for use with cameras having image sensors larger than 24x16mm, or 35mm film cameras. The lens is available in Canon EF, Konica Minolta AF-D, Nikon AF-D, and Pentax AF mounts and is maximized for smaller-sized imaging chips.

The lens is compact, smaller than you might think, because the use of extra refractive index optics permit a smaller lens diameter while maintaining the same aperture values as similar lenses. An internal focusing system provides improved optical characteristics by minimizing light loss in the corners and suppresses focusing aberrations, but my favorite feature is the AF18-200mm F/3.5-6.3's short minimum focus distance (17.7") that at 200mm permits macro-like capture. Low Dispersion (LD) glass elements compensate for chromatic aberrations that can create problems at the telephoto end of the 18-200mm range.

Out Here In The Real World
I didn't photograph any lens resolution charts with Tamron's AF18-200mm F/3.5-6.3 lens and I'll bet you won't either. Instead I attached the lens (see "Canon Mount") on two different Canon EOS digital SLRs and captured images with a wide range of subject matter under many kinds of lighting and environmental conditions. Through it all, I never encountered any kind of mechanical or optical flaw in the lens that prevented me from capturing the image I wanted. While photographing drag races with two different Canon digital SLRs with the Tamron mounted on one and a Canon EF zoom on the other, I was struck by how much faster the AF18-200mm F/3.5-6.3 lens focused than the Canon lens. Because of the AF18-200mm F/3.5-6.3's internal focus mechanism, manual focusing with the lens was fast and crisp, too, but I rarely used it that way.

This photograph of a classic Ford Thunderbird was made at The Mathews Collection (www.mathewscollection.com). Yup, there are two other classic T-birds parked right behind it. I attached Tamron's AF18-200mm F/3.5-6.3 lens to a Canon EOS 20D that was solidly mounted on a Manfrotto tripod. Exposure in Aperture Preferred mode at ISO 400 was 3.2 seconds at f/40 to maximize depth of field. After reviewing the histogram of a few test exposures, exposure compensation was set at +1/3 stop.
All Photos © 2005, Joe Farace, All Rights Reserved

"Without" moving the tripod from the original shot of the Thunderbird, I zoomed the Tamron AF18-200mm F/3.5-6.3 lens to 18mm to demonstrate its wide 11.1:1 zoom ratio. This exposure was 1.3 seconds at f/22 in Aperture Preferred mode at ISO 400. A +1/3 stop exposure compensation was used. Now, the Thunderbird, which previously filled the frame, is seen as a small car parked in the middle of a much larger collection that features several rare McLaren automobiles in the foreground.

The build quality of the lens is appropriate for its price point and maybe just a touch better than you might expect and its compact size makes you want to keep it on your camera all day. By using an image circle designed to match that of smaller-sized imaging chips, Tamron produced a lens as compact as its 28-300mm lens, and, depending on your camera's multiplication factor, offers the same angles of view.

Venues with interesting architecture and landscaping, such as the Arvada Center for the Arts and Humanities, make interesting infrared photography subjects. I mounted the Tamron AF18-200mm F/3.5-6.3 lens onto a Canon EOS D30 that was modified (www.irdigital.net) to capture infrared images. The lens was set at 18mm, but since Tamron's 18-200mm lens is designed for digital cameras with smaller-sized imagers, the D30's 1.6x multiplication factor produced a focal length equivalent of 29mm. Exposure was 1/100 sec at f/16 in Aperture Preferred mode at ISO 400. A +1/3 stop exposure compensation was used to open up the "white" tree leaves.

A "tulip" lens hood is included with the lens and did an effective job of controlling flare at the 18mm focal length except in those extreme cases where the sun was shining directly into the lens. Even then, flare was well controlled and while present (I always like to use flare as a compositional element) never significantly reduced the overall contrast of the shot. Sharpness was very good at all focal lengths and with many different kinds of subject matter, varying from portraits to landscapes to digital infrared architectural images. I used the lens to photograph everything from close-ups to flowers to tire-smoking dragsters and never felt like I wanted anything more.

Dramatic drag racing images are possible with Tamron's AF18-200mm F/3.5-6.3 lens even from the grandstands. For this shot, the lens was attached to a Canon EOS 20D and panned to follow the action of this funny car. Exposure was 1/80 sec at f/18 in Aperture Preferred mode at ISO 200.

Backlit infrared? There are all kinds of so-called "rules" about "when" you can capture infrared images, but I've found that the best way to learn is to make pictures and observe the results on the digital camera's preview screen. Sometimes you'll be surprised as I was with this backlit shot of trees made at the Arvada Center for the Arts and Humanities. I used a modified Canon EOS D30 with the Tamron AF18-200mm F/3.5-6.3 lens set at 22mm. Exposure was 1/200 sec at f/10 at ISO 400.

All of the pundits will tell you that you should only make infrared photographs in bright sunlight, but I photographed this nearby farm when a storm was approaching. The brooding effect of the storm clouds, combined with the typical infrared effects on the trees, produced an infrared image I thought was anything but normal. Camera was a modified Canon EOS D30 with the Tamron AF18-200mm F/3.5-6.3 lens at 200mm. Exposure was 1/200 sec at f/10 at ISO 800.