The Kobalux wide-angle lenses were produced from 1981 until 2002 by the chief lens designer, Abe-san, who started his own company, Avenon Kohki (Y.K. Optical) after Sankyō Kōki K.K. (三協光機㈱) who produced the cult Komura lenses, became insolvent in 1980.
The Kobalux Wide 28/3.5 was sold as Avenon, Pasoptik, Bower, Adorama and is one of the most compact 28mm wide-angle lens for rangefinder cameras, featuring excellent optical performance, sharpness, tonal character and minimal distortion across the entire image area.
Originally made in 1981 in chrome with distinctive round focusing tab and a six-blade diaphragm and minimal focus to 1 meter. The second generation, or "M-series", was sold in black with a silver rim. It has a crescent-shaped focusing tab, an eight-blade diaphragm, grip tabs on the aperture ring and minimal focus to 0.75 meter.
the Kobalux / Avenon Super Wide 21mm F 2.8 lens was sold under several different names. In Japan it was called Avenon, in North America usually Kobalux, and it seems that it was also sold in United Kongdom under the name Pasoptik and possibly also under other names.
Y.K. Optical also produced 21mm viewfinder for the lens. Sometimes the viewfinder was included with the lens and sometimes it was not. At least in Japan, the Millennium Edition was sold without the viewfinder, though the lens always came with a small metal hood.
When mounted on a camera, the lens protrudes deeply into the camera body. Because of this, it cannot be mounted on some cameras, notably on Canon series V cameras, Canon series VI cameras (Canon P, etc.), and Canon 7. On these late Canon Leica Screw Mount bodies the lens would hit the camera's internal light shield.