Some users believe that this is the best f1.2 lens every made. This lens was made to be used on the Konica AR mount SLR cameras. However, none of the Koinca AR SLR bodies, from Auto-reflex to T3N, display the 1.2 aperture size in their viewfinder.
The lens is great, but not perfect. The yellowish color in the glass elements, especially in the earlier versions of this lens, is bothering the color film shooters. This is caused by the materials used to make the glass. With aging, the yellow color showed up. But using the auto color balance in a digital camera, this issue is not a problem any more. In the late version of the lens, the rubber surface layer on the focusing ring may peel off. Therefore, I prefer the older versions with an all-metal focusing ring.
This wonderful lens can be bridged to many DSLR or mirrorless digital bodies via a matched adapter. Given no new supply in the market, the price for the used ones is increasing over the past years.