With Pentax now incorporating shift CCDs into its cameras, there's no need to add stabilisation to their lenses so the 50-200mm uses a standard Pentax KAF mount......
Pentax DA 50-200mm 4-5.6 ED Review
With Pentax now incorporating shifting CCDs into its cameras, there’s no need to add stabilisation to their lenses so the 50-200mm uses a standard Pentax KAF mount. Unlike the newer DA* lenses, the lens lacks the SDM module that allows quieter and faster AF control.
This point about the lack of SDM in particular, marks the lens out from comparable Canon and Nikon models in this category. While they are smooth and silent, the Pentax is whirry and slow. On the other hand, unlike the Canon optic, at least the Pentax one does have a decent manual focus grip!
In addition, the lens features a Quick-Shift Focus System, whereby you can use the manual focus ring even in autofocus mode. Another thoughtful touch is a focus distance scale near the focus ring, so you can set the hyperfocal or pre-focus distance if need be.
In terms of sharpness we’d class this lens as acceptable, with a solid performance throughout the aperture range but failing to set the world alight with its sharpness. Chromatic aberration control is also mostly average, though central control at 50mm is well maintained.
Verdict
Really a budget or starter lens, reasonably priced, but lacking the fast maximum aperture and expensive glass of more professional lenses