Pentax's flagship fast fifty — the HD D FA* 50mm f/1.4 SDM AW for full-frame K-mount.
The Pentax HD D FA* 50mm f/1.4 SDM AW is Pentax's flagship standard prime, designed for the K-1 full-frame DSLR. The Star (*) designation indicates Pentax's absolute highest optical tier. D FA confirms full-frame coverage. SDM provides in-lens ultrasonic autofocus. AW (All Weather) indicates full weather sealing. This is Pentax's finest 50mm lens.
Optical performance is outstanding. Sharpness is excellent from f/1.4 — a significant improvement over earlier Pentax fast fifties. The Star designation means this lens uses premium optical materials and design. HD coating provides superior light transmission. Bokeh is smooth with nine rounded aperture blades. Coma and aberrations are excellently controlled.
Pentax K mount, full-frame with SDM ultrasonic autofocus. Filter thread is 72mm. Weight is approximately 910 grams — heavy for a 50mm, reflecting the premium optical design. Build quality is outstanding with AW weather sealing (dust, splash, freeze to -10°C). The SDM motor provides lens-based AF independent of the body motor. Electromagnetic aperture.
Available on the used market at moderate prices. Check AF accuracy, weather seal integrity, and clean optics. Pentax's finest fast fifty and one of the best 50mm lenses available in any system. The AW weather sealing paired with the K-1's sealing creates a truly all-weather professional kit. The weight is the main practical concern.