In The Final Analysis
After working with the AT-X 535 PRO DX, I could easily see where the “PRO” moniker comes from. The lens feels solid and performs admirably in terms of physical operation. Optically, I found it to be a superior piece of glass. While the lens did show a drop in performance at or near the close-focusing limit, being especially soft at maximum aperture, stopping down even 1⁄3 stop showed a dramatic improvement. Edge sharpness also fell off at this range. At normal shooting distances, performance was fairly constant at each f/stop and throughout the zoom range—namely, remarkable.

The Tokina AT-X 535 PRO DX uses a One-Touch Focus Clutch Mechanism to go from autofocus to manual focus, without having to resort to an AF/MF switch. This mechanism makes it possible to keep your hand on the focusing ring while changing from one Focusing mode to another. Also note how wide and conveniently close these nicely textured zoom and focusing rings are.

What was especially noteworthy about the lens was that, when shooting wide-open, optical vignetting was practically indiscernible, in contrast to some other zooms I’ve worked with in this range. Also, barrel and pincushion distortion, while observable at the 50mm (equivalent 75mm) and 135mm (equivalent 202mm) settings, were very well corrected at interim focal lengths. Of the two, barrel distortion was the more pronounced, but not to a disturbing degree. What’s more, the nine-bladed iris diaphragm, while not yielding a truly circular aperture, still managed to produce pleasing background softness and nearly circular out-of-focus highlights. All in all I was really impressed by the Tokina 535 tele-zoom’s performance and I can see it becoming a favorite lens.

I spied the squirrel about 8 or 10 ft away, focusing manually to avoid tree branches. Suddenly he jumped onto a tree trunk only a few feet away. I didn’t have time to do more than focus, standing my ground and following his movements, all the while a bit worried his next leap might be in my direction. Owing to low-light levels, I set ISO to 1600 for an exposure of f/9 at 1/320 sec.

Technical Specifications
Sensor/Mount: APS-C/Nikon D, Canon EOS
Focal Length: 50-135mm
Max. Aperture: f/2.8
Min. Aperture: f/32
Optical Construction: 18 elements/14 groups
Min. Focus Distance: 39.3”
Reproduction Ratio: 1:5.9
Filter Size: 67mm
Dimensions: 3x5.3”
Weight: 29.8 oz
Lens Hood: Petal-shaped
Street Price: $649

For more information, contact THK Photo Products, Inc., 7642 Woodwind Dr., Huntington Beach, CA 92647; (800) 421-1141; www.thkphoto.com.