The Yashica ML 42-75mm f/3.5-4.5 is a first-party standard zoom that Yashica produced for its FX and FR-series SLR bodies from the late 1970s, offering a compact wide-to-short-telephoto range as an alternative to a fixed standard prime.
Built in Yashica/Contax C/Y bayonet mount, the lens uses a one-touch push-pull zoom and focus collar typical of standard zooms from this period, with a multi-coated ML optical formula intended to match the contrast of Yashica's contemporary prime lenses. It shares its mount with Carl Zeiss lenses made for the same Contax/Yashica system.
Rendering is respectable at the wide end, softening somewhat toward 75mm and at maximum aperture, typical of consumer standard zooms of its generation rather than the sharper Zeiss optics sold alongside it on the same mount. It offers useful everyday flexibility rather than standout optical character.
Used examples are inexpensive and fairly common, often sold alongside Yashica FX-series bodies as a kit combination. Buyers should check the push-pull zoom collar for looseness or zoom creep and confirm the aperture blades move cleanly through their full range.