Pentax calls this $215 optic a kit lens, even though it’s not currently bundled with any DSLR body. (We bet that this fall we’ll see a dual-lens package with this and the 18–55mm WR zoom, if only from mail-order dealers.) It’s the first kit telezoom that’s weather-resistant, thanks to six O-rings and gaskets surrounding the front element, lensmount, and zoom and focusing rings.
The lens is compact enough to throw no shadow when used with the built-in flash on our test camera, the Pentax K-7; the length is about average for its class. It’s slightly lighter and thinner than usual, though, taking a smaller filter size than the typical 52mm.
The zoom ring is very well damped; the manual-focus ring, a little less so. Both are clad in knurled rubber, rare at this price.
The focusing collar has a very long turning radius (200 degrees, more than twice the average). This enables very precise focusing—a good thing, because autofocus is this optic’s weakness: It was quite noisy and sluggish on the K-7.
On our optical bench, tests for sharpness and contrast found Excellent SQF numbers at all focal lengths except 200mm, where it dipped into the Very Good range. While this was common a decade ago, kit telezooms these days increasingly produce Excellent-range SQF numbers when fully racked out.
Its edge falloff, macro performance, and even the impressive Imperceptible barrel distortion at 50mm (0.05%), as measured by our DxO Analyzer 3.2 tests, are also average by today’s kit zoom standards.
If you’re an active, outdoorsy type, this well-priced weather-resister (along with the well-sealed bargain of the Pentax K-7) makes a fine telezoom. But if you need a responsive AF system for fast-moving subjects, keep shopping.
Specifications: 50–200mm (50.01–193.26mm tested), f/4–5.6 (f/3.80–5.81 tested), 11 elements in 10 groups. Focus ring turns 200°. Zoom ring turns 90°. Focal lengths marked at 50-, 80-, 100-, 135-, and 200mm.
Diagonal view angle: 31–8 degrees
Weight: 0.68 lb
Filter Size: 49mm
Mounts: Pentax KAF
Street Price: $215
Distortion: At 50mm, 0.05% (Imperceptible) barrel. At 100mm, 0.22% (Slight) pincushion. At 200mm, 0.23% (Slight) pincushion.
Light Falloff: At 50mm, gone by f/5. At 100mm, by f/5.6. At 200mm, by f/8.
Close Focusing Distance: 44.8 inches.
Maximum Magnification Ratio: At 50mm, 1:15.28. At 100mm, 1:7.78. At 200mm, 1:3.97.