Pentax's classic fast fifty — the K-mount f/1.7 nifty fifty that defined a generation of Pentax shooters.
The Pentax SMC 50mm f/1.7 is a classic manual focus standard prime from Pentax's K-mount film era. Part of the M-series or A-series depending on the specific version, it was the default fast fifty for Pentax shooters throughout the late 1970s and 1980s. The SMC (Super Multi Coating) designation indicates Pentax's high-quality multi-layer coatings.
Optically this is a well-regarded vintage fifty. Sharpness is good from f/1.7 in the centre and excellent by f/4 across the frame. The six-element optical design is simple but effective. Bokeh is reasonably smooth with some nervous tendencies in busy backgrounds — typical of fast fifties from this era. Flare resistance is good thanks to SMC coatings.
Pentax K mount, manual focus. Filter thread is 49mm. Weight is approximately 185 grams — compact and light, reflecting the Pentax M-series design ethos. Build quality is excellent with smooth metal construction and a well-damped focus ring. The K-mount bayonet means it fits every Pentax DSLR ever made, with stop-down metering on digital bodies.
Very common and affordable on the used market. Check for haze, fungus, and smooth aperture ring operation. Pentax's K-mount backward compatibility makes this usable on modern K-3 III and other digital bodies. An excellent budget fast prime that delivers great results for the price — the Pentax-A 50mm f/1.7 adds auto-aperture for digital convenience.