Pentax's A-series wide zoom — a manual-focus 24-50mm f/4 with a constant aperture and 'A' setting.
The SMC Pentax-A 24-50mm f/4 is a wide-to-standard zoom for the Pentax K bayonet mount, from the A-series generation with the 'A' aperture position for program and shutter-priority automation. It covered a useful wide range in a single lens for travel and general work.
This is a manual-focus lens with a 24-50mm zoom range and a constant maximum aperture of f/4 across that range. It carries Super Multi Coating and an 'A' aperture setting for camera-controlled exposure. Exact construction and filter thread should be checked on the individual sample.
The 24-50mm span runs from a broad wide angle to a short standard, making it flexible for landscapes, interiors, street scenes and everyday shooting without a lens change. The constant f/4 aperture keeps exposure steady through the zoom range.
Constant-aperture wide zooms from the A line are practical adapting lenses, though they are heavier than the primes. Inspect the zoom and focus action for smoothness and any wobble, check for internal haze, fungus and dust, and confirm the aperture is dry. It fits Pentax K digital bodies and adapts to mirrorless.