Pentax's A-series short tele — a manual-focus 100mm f/2.8 with an 'A' aperture setting.
The SMC Pentax-A 100mm f/2.8 is a short-telephoto prime for the Pentax K bayonet mount, from the A-series generation with the 'A' aperture position for program and shutter-priority automation. This is the non-macro 100mm, distinct from the A Macro version.
This is a manual-focus lens with a 100mm focal length and a maximum aperture of f/2.8, carrying Super Multi Coating and an 'A' setting for camera-controlled aperture. Element count and filter thread should be confirmed on the specific sample rather than assumed.
At 100mm the short-telephoto perspective flatters portraits and isolates subjects, and the f/2.8 aperture yields a shallow depth of field with smooth backgrounds. It suits portraits, tighter general framing and low-light work where reach and separation are wanted.
A-series short telephotos are valued for the 'A' aperture automation on later bodies and their compact form. Confirm the 'A' position locks in, inspect for haze and fungus, check the aperture is dry, and test the focus ring for smooth action. It fits Pentax K digital bodies and adapts to mirrorless.