Pentax HD D FA 150-450mm f/4.5-5.6 ED DC AW — weather-sealed super-tele zoom for K-mount
The HD Pentax-D FA 150-450mm f/4.5-5.6 ED DC AW is a full-frame super-telephoto zoom built for Pentax's K-mount digital SLRs, designed to cover 35mm-format sensors such as the K-1. It sits alongside the D FA* line as Pentax's main affordable option for wildlife and sports shooters needing extended reach.
The optical formula is 18 elements in 14 groups, including ED glass, with HD and SP coatings on the front element. It has an 86mm filter thread, weighs about 2000g before hood and tripod foot, and focuses down to 200cm. The 9-blade diaphragm runs f/4.5-5.6 to f/22-27, with an in-lens DC autofocus motor, Quick-Shift manual override, AF buttons on the barrel, a focus range limiter and a removable tripod mount.
Its all-weather (AW) sealing and rounded diaphragm give it an edge over Pentax's older screwdrive telephoto zooms for outdoor use, and the internal-focus DC motor keeps the front element stationary during zooming and focusing. Reach at 450mm with a moderate f/5.6 makes it a practical, if heavy, one-lens wildlife kit.
It remains in current production, so used examples on the UK market are typically recent trade-ins rather than aged stock. Buyers should test the AF motor for smooth, quiet operation, check the tripod collar rotates freely, and confirm the AW gaskets and rear seal are intact given the lens's outdoor use case.