The Pentax HD DA 20-40mm F2.8-4 ED Limited DC WR ($799.95) is the first zoom in the company's Limited lens series, as well as the first in the series to boast a weather-sealed design. Its zoom range is modest, at just 2x, but it's compact and an all-metal build gives it a premium look and feel. If you value its size and want an all-weather zoom, it's a solid choice for an APS-C Pentax system. But if you don't mind a larger lens, the Sigma 17-70mm F2.8-4 DC Macro OS HSM offers more coverage on both ends and is less expensive. For the same price you can opt for another short zoom, our Editors' Choice Sigma 18-35mm F1.8 DC HSM, which maintains a bright aperture throughout its range, but is much larger and heavier than the 20-40mm. DesignThe 20-40mm is not that far off in size from a typical 18-55mm zoom lens, but it's clear that the build quality is much higher. It measures 2.7 by 2.8 inches (HD), is compatible with 55mm threaded filters, and weighs about 10 ounces. The barrel is me...
The Pentax HD DA 20-40mm F2.8-4 ED Limited DC WR is a compact, weather-sealed zoom lens, but its range is limited and it's priced on the high side.
Sharp throughout zoom range; Weather-sealed design; Compact; Metal lens barrel
Pricey; Some distortion at the wide end; Modest zoom range