Summicron 35mm f/2 (v4)

By 1979 Leitz had refined the 35mm Summicron through three versions. The fourth iteration was smaller and lighter than its predecessors, and its seven-element formula happened to produce a background rendering — bokeh — that struck photographers as unusually smooth and pleasing. The nickname "Bokeh King" emerged organically in online forums during the film revival of the 2000s and has stuck ever since.

For beginners: "bokeh" is the Japanese-derived term for the quality of out-of-focus areas in a photograph. A lens with good bokeh renders background highlights as smooth, rounded discs; poor bokeh turns them into harsh rings or cats-eye shapes. The v4's bokeh quality comes from the specific design of its aperture blades and the residual spherical aberration the designers chose to leave in the formula. It is not the sharpest version of the Summicron 35 at any aperture, but for many photographers sharpness is not the point. At 160g it is also the lightest 35mm Summicron ever made for the M mount.