It may have a long name but the Tamron's focal length range is short, covering the equivalent of just 16.5-27mm...
It may have a long name but the Tamron’s focal length range is short, covering the equivalent of just 16.5-27mm (based on 1.5x magnification in 35mm terms). Tamron also makes this lens available in Nikon and Sony mounts, but doesn’t support Pentax cameras. Incidentally, Sony mount lenses will also fit Konica Minolta cameras.
The Tamron optic uses a variety of aspherical lenses, one glass-moulded lens and two hybrids, as well as one Low Dispersion (LD) and one High Index Dispersion lens (HID). Tamron doesn’t claim any special AF assistance motors within this lens, and you can feel and hear the difference. While AF is relatively quick, it is marginally slower than on comparable optics, and switching from short to long-range focusing is audibly more noticeable as the motor whirrs and grinds.
It’s also worth noting that the focusing ring rotates as you focus in AF mode and if your grip happens to be on the focus ring it will offer resistance against the AF motors. Also, there’s no facility for manual focusing in AF mode, so you’ll hear the motors whirring and worry that you’re going to grind the gears. The zoom ring is free flowing without slackness.
Tamron’s sample shots are more than adequate, though there are plenty of examples of chromatic aberration, especially in the corners of the frame at 11mm. Similarly image sharpness falls off at the corners, though contrast is generally good.
The Tamron is lacking compared to the others. It's not a bad lens on its own, but doesn’t stand up to the competition