The Olympus OM-System Zuiko 75–150mm f4 is a compact, all-metal manual focus telephoto zoom lens designed for Olympus OM-mount 35mm SLRs. Introduced in 1972 as Olympus’s first zoom lens, it offers a constant f/4 aperture throughout its 2x zoom range. The lens features a two-ring design for separate zoom and focus control, a built-in retractable lens hood, and a minimum focusing distance of 1.6 meters. While image quality may show softness and chromatic aberrations wide open, stopping down improves sharpness, making it suitable for portraiture and general telephoto use. Its compact size and 49mm filter thread make it a convenient addition to any OM system kit.