Minolta's fast MC wide — the 28mm f/2.5 MC W Rokkor-SI, a versatile mid-60s reportage prime.
The Minolta MC W Rokkor-SI 28mm f/2.5 is a wide-angle manual-focus lens for Minolta reflex cameras from the MC generation of the mid-1960s. The W prefix denotes its wide-angle role and MC the meter-coupled line. A fairly fast 28mm, it was a popular reportage and landscape wide in Minolta's meter-coupled range.
This is a manual-focus wide-angle lens with a 28mm focal length and a maximum aperture of f/2.5, from the meter-coupled MC series. The SI code encodes the element and group arrangement in Minolta's naming scheme. Only the focal length and aperture are affirmed; other construction figures are not confirmed here and are omitted rather than guessed.
The 28mm focal length is a versatile wide angle for landscapes, street photography and travel, wide enough to take in a scene without the extreme perspective of an ultra-wide. Its moderately fast f/2.5 aperture aids handheld shooting in lower light and composition, with MC-era coatings giving decent contrast for the period.
On the used market this is a well-regarded MC wide Rokkor bought by collectors and users adapting vintage glass. Owing to its age, inspect for haze, fungus and separation, confirm the aperture is dry and responsive, and ensure the focus helicoid moves smoothly. Check the coatings for cleaning marks, and fit an adapter for mirrorless use.