Tamron’s AF18-250mm F/3.5-6.3 Di-II LD Aspherical (IF) Macro
Versatility In A Compact Super Zoom

by George Schaub

Weighing in at just under 16 oz and with closed dimensions of a mere 2.9x3.3”, the latest all-in-one zoom from Tamron is a very handy traveling companion. Priced at a bit under $500 (street price), the lens is for APS-C D-SLRs only, and will yield about 28-375mm (35mm equivalent) on most (1.5x; slightly more on Canon amateur models) D-SLRs. The price and variable aperture tell you that this is not expected to be a pro-caliber lens, but for many D-SLR owners this might be the only lens they need carry on their next voyage, be it a visit to a new city or a hike through the hills.

Tamron set out to design a compact power zoom that would not skimp on quality or range and for the most part have succeeded in delivering both. There’s no question that a 13.9x tele is a remarkable feat, albeit at the price of an f/6.3 maximum aperture at the tele end. Were this a lens for a film camera this max aperture might eliminate it from consideration, but with digital it can be compensated for by simply raising ISO to a reasonably high speed. Necessarily, you need to make sure shutter speed is such that you will not create camera shake when working racked out; I generally work with Shutter Priority at the longer focal lengths and strive to shoot at 1/500 sec when possible. However, I did shoot a few night scenes with the lens and properly braced it did just fine. Shake, as you know, is mostly operator failure and only somewhat camera failure, although having a fairly narrow max aperture makes you aware of it more than if you had a faster lens.

Speed matters aside, Tamron has put together all their impressive lens-making know-how to deliver excellent image quality. As the name implies the lens has LD (Low Dispersion) and AD (Anomalous Dispersion) elements to minimize chromatic aberration. It also utilizes what Tamron calls “Internal Surface Coatings” to reduce ghosting and flare, two of the hidden enemies of digital image quality (and why shooting with a lens hood is even more important than it was when working with film; Tamron does supply a flower-shaped lens hood with the lens). These coatings are in addition to multi-coating the lens front element as well.

The versatility of the Tamron 18-250mm lens is evident in both close focusing and when gathering in distant subjects. The crisp edges and edge contrast are both shown in this shot of an old pickup truck in Taos, New Mexico. Exposure with a Canon 30D at ISO 200 was f/13 at 1/320 sec at the 18mm focal length. Without moving from the shooting distance this classic Chevy emblem was captured along with the wonderful patina of this old desert truck. Exposure was unchanged but lens was racked out to frame the logo. All Photos © 2006, Grace Schaub, All Rights Reserved

And while particulars are proprietary, Tamron tells us that the lens uses an optical system that is designed to “confine the changing angles of incidence of light rays reaching the imager within a certain scope over the entire image field by considering the effects of variance due to zooming.” That mouthful means that the lens is designed for digital from the ground up and not just as an adapted 35mm design.

Another plus of this lens, and why it becomes increasingly obvious why we dub it an “all-in-one” is its close-focusing ability, which is 17.7” throughout the entire focal length range. When racked out to the maximum focal length this means no more need to position yourself to avoid casting a shadow when doing close-ups, although depth of field at the max range is necessarily shallow.

Don’t try this at home, but the shot was made directly into sunrise to capture this amazing scene, and coincidentally check for flare. Exposure at ISO 1000 was f/22 at 1/2500 sec at 39mm focal length. The blazing light did not cause any glare or streaks in the image, a testament to excellent coating and ghosting control.

The fit and finish are quite good, with a bit of gold banding to give it an upscale look and metal mount in all fittings. There’s also a zoom lock mechanism to avoid the dreaded “zoom creep” when carrying the lens. Rubber patterns and grip on the zoom and focus ring finish off the nice look and feel of the lens.

The 18-250mm focal length range is amazing to work with in the field, as it covers the bases and then some. These two shots were made at the extreme ends of that range. Both were shot at ISO 200. The valley floor was exposed at f/8 at 1/1000 sec; the wide view at f/8 at 1/1600 sec.

Overall the new Tamron 18-250mm is a phenomenal piece of design and engineering. It delivers a very wide focal length range in a very compact package. While the lens more than doubles in size extension when zoomed out to the max, it fits very handily in a fanny or sling pack when on the move. And image quality in various lighting and shooting conditions was excellent. Although that narrow maximum aperture at the longer focal lengths might give you pause, there’s no question that the price is right for such a versatile lens. I wouldn’t hesitate to take it along on a casual trip or vacation.

For fun a shot was made at night in the old Taos Plaza. Edges are crisp and full moon and hotel sign fail to create flare, showing the even greater versatility of this lens as an all day and night traveling companion. Camera was propped up on the roof of a car and exposure at ISO 1250 was f/5 at 1/6 sec. All shots were made with the Canon 30D.

For more information, contact Tamron Lenses USA, Inc., 10 Austin Blvd., Commack, NY 11725; (800) 827-8880; www.tamron.com.