Nikkor E Series and Kaleinar-5N 100mm F2.8?

Who know that lenses?

sharpness, contrast, bokeh

The Nikkor "E series" lenses were designed with two goals. A lightweight lens for use with the Nikon EM cameras and priced to enable new photography enthusiasts to buy a 35 mm SLR with a minimum investment.

All Nikkor "E" lenses are AI-S, so can be used with a host of 35 mm SLR cameras.

The Kaleinar-5N 100mm F2.8 is a lens made in the Soviet Union and came with Nikon F-mount

There were three Soviet cameras which used the Nikon F-mount: The KIEV-17, 19 and 20. They used the Kaleinar lenses with Nikon mounts

If you follow the link under source, you will see that many of the E lenses used the same lens formuli, but mounted in a lens body which made use of plastic parts to create a lighter lens.

The only way to know what kind of out of focus backgrounds (Bokeh) is to mount lenses on a camera and see for yourself. What I consider pleasing out of focus backgrounds, may not match your idea of an ideal out of focus background.