Minolta's early-60s ultra-wide — the 21mm f/4.5 W Rokkor-PI, a scarce collector's Rokkor.
The Minolta W Rokkor-PI 21mm f/4.5 is an early ultra-wide manual-focus lens for Minolta reflex cameras, dating from the early 1960s. The W prefix marks it as a wide-angle Rokkor. This lens is notable as one of Minolta's early ultra-wide designs of a type that required the mirror to be locked up on some bodies, sitting at the extreme wide end of the range for its time.
This is a manual-focus wide-angle lens with a 21mm focal length and a maximum aperture of f/4.5. The PI designation encodes the element and group arrangement in Minolta's naming scheme. Beyond the confirmed focal length and aperture, detailed construction figures for this specific model are not verified here and are left out rather than estimated.
The 21mm field of view is very wide, lending itself to grand landscapes, cramped interiors and architectural subjects where sweeping coverage matters. The f/4.5 maximum aperture is modest, so the lens is at its best in bright light or on a tripod, where its ultra-wide perspective can be exploited fully.
On the used market this is a scarce early Minolta wide-angle mostly of interest to collectors and dedicated system users. Because of its vintage, examine it for internal haze, fungus and separation, check the aperture for oil and smooth action, and confirm the focus helicoid is not stiff. Look closely at the coatings for wear and cleaning marks before committing to a purchase.