- Nice balance and robust feel
- Slightly stiff and jerky zoom action
- Review Price: £480
The gold ring around the front of its barrel tells you that this is a serious lens. Its f/2.8 maximum aperture is maintained right across the zoom range and although this results in a rather large lens it is very well balanced and therefore comfortable to hold and use. Cosmetically, however, it is a shame that the zoom action pushes the front element so far forwards (about 36mm) when the focusing mechanism is entirely internal.
The manual-focus ring is generous and has a throw of around 60°, which provides a rapid response but may be slightly too short for precise use at speed. The zoom ring is closer to the camera body and rather narrower: sadly, our review lens had a slightly jerky zoom action and the movement as a whole was rather stiff. Automatic focusing is very quiet but the lens’ AF speed left a lot to be desired on the K200D review body.
Any attack from the elements shouldn’t be a worry since Pentax DA* lenses are protected against inclement weather.
On paper this is a well-specified lens and the price reflects this, however its potential was not fully realised during testing.
Although the f/2.8 maximum aperture is useful for low-light and controlled depth-of-field photography, its use results in colour fringing at the edge of the frame, as well as comparatively poor sharpness figures with the exception of when it is fully stopped-down to f/22. On the other hand, closing down just one f-stop improves the recorded sharpness significantly. Distortion is well controlled and should never be a significant concern.
Within the DSLR sector Pentax shares the same lens mount as Samsung, which opens up additional options when it comes to choosing lenses. Samsung offers a 16-45mm f/4 and an 18-55mm f/3.5-5.6, both of which mirror lenses offered under the Pentax brand in terms of specification and price.
Turning to true third-party manufacturers, Sigma has a 17-70mm f/2.8-4.5 lens as well as an 18-50mm zoom that comes in a Pentax mount as both fixed-aperture (f/2.8) and variable-aperture (f/3.5 -5.6) versions.
Tamron offers a less expensive f/2.8 fixed-aperture zoom covering 17-50mm and there is also a 16-50mm f/2.8 zoom from Tokina.
The most expensive of the Pentax lenses in this category 16-50mm did not always deliver everything that it promised. In particular, the f/2.8 aperture is more for bright viewing than it is for top-quality imaging. Similarly, the SDM system is indeed smooth and quiet but the lens was positively sluggish in comparison to other lower priced offerings in this range from Pentax.
Score in detail
Image Quality 9