Tamron SP AF 17-35 mm f/2.8-4 Di LD Aspherical (IF)
10. Autofocus
Although the speed of the autofocus in the tested Tamron is inferior to the speed of an ultrasonic mechanism, the focusing process can hardly be called slow. The lack of ultrasonics is rather heard than seen because during the autofocus work we can notice high-pitched noises. It is not the biggest disadvantage, though. More serious problems concern the repeatability of the autofocus work- the lens in studio conditions missed in 12% of shots, a result you can hardly call good. The misses were so huge that they were easily noticeable to the naked eye; you could see on the lens’s distance scale that, after every refocusing the lens chose a different position although the distance to the chart didn’t change at all. It’s a pity because such a patchy performance means we will not always be able to make use of the perfect sharpness in the frame centre to full advantage.
Missing so often the autofocus doesn’t prefer any of the side so we can’t say it has any front or back-focus tendencies.
