PENTAX 21387 DA 16-85mm f/3.5-5.6 ED DC WR camera lens

Pentax KAF3 zoom lens

The HD Pentax-DA 16-85mm f/3.5-5.6 ED DC WR covers a 24.5-130mm equivalent focal range on APS-C bodies. Its 5.3x zoom spans wide landscapes through to short telephoto portraits in a single weather-resistant barrel. Autofocus is driven by a DC motor with quick-shift manual override for immediate tactile control. The 72 mm filter thread accepts standard circular filters and the supplied PH-RBA hood.

Upgrade from fixed focal length or kit zoom

Photographers carrying a prime or a shorter kit zoom gain continuous 16-85mm coverage without swapping glass. The jump is worth it when a single lens must handle architecture, street scenes and candid portraits in changing light. The variable f/3.5-5.6 aperture and 0.26x maximum magnification limit low-light subject isolation and close-up detail work. Buyers needing constant f/2.8 brightness or 1:1 macro reproduction will not find them here.

KAF3 mount and variable aperture constraints

The lens mounts only on Pentax KAF3-compatible DSLRs and transmits aperture electronically; no mechanical aperture ring is present. At 85mm the maximum aperture narrows to f/5.6, reducing viewfinder brightness and requiring higher ISO or slower shutter speeds indoors. Minimum focus distance is 1.15 ft (0.35 m) across the zoom range, yielding 0.26x magnification at the long end. The 16-element, 12-group design with ED and aspherical elements controls aberrations, yet diffraction softens detail beyond f/22-38.