The Tokina AT-X 16.5-135mm f/3.5-5.6 DX features an attractive wide-angle as well as a useful tele-photo zoom range
The front half of the lens barrel is home to the manual-focus ring, which is enabled on the camera body rather than on the lens itself. The ring has a light touch and a very short throw of only about 30; it is complemented by a focused-distance scale but there are no depth-of-field markings.
The rear half of the lens barrel is filled with a generously-wide zoom ring that, on the review sample, felt rather stiff. Extending the lens to its maximum focal length approximately doubles its overall length. There’s a reversible, petal-type lens hood but there is no image stabilisation system, which would be useful at longer focal lengths.
Another improvement would be to fit an internal-focusing mechanism as the manual-focus ring currently rotates in AF mode, so you need to adopt a careful grip on the lens. This can prove especially tricky when the lens is fully extended as this causes the balance of the lens to move forward.
Field testing revealed that the rather stiff zoom ring feels very heavy after a while and could do with slight loosening for more comfortable use. Similarly, the camera-body AF/MF selector is less convenient than an on-lens slider switch but the short-throw focusing action proved not to be a problem. The wideangle setting is generous but the other end of the zoom (135mm at f/5.6) is less impressive and is likely to fall short in some situations.
The reversible lens hood is as obstructive as such things always are (insofar as the manual-focus ring is concerned) but it does provide a comfortable outer grip for the lens that avoids interfering with the manual-focus ring.
Technical testing revealed a solid performance for mid-range aperture settings but wider apertures are generally weaker, which is a shame in a lens that does not have a particularly fast maximum aperture. There were also clear signs of chromatic aberration at both ends of the zoom range and this was also apparent in some real-world images.
The zoom works best, in terms of high MTF (Modular Transfer Function) and negligible chromatic aberration, at its 70mm setting but is most consistent at 16.5mm.
Although there is very slight field curvature at the edge of the frame this is not a significant issue and will undoubtedly go completely unnoticed in most pictures.