This is a Russian built lens on an m42 pentax mount. Its a copy of a Carl Zeiss T plannar designed before WW2 but newer ones such as mine are multicoated and fairly modern. (many of these can be found on ebay and are easily adaptable to all DSLRs) I found this lens on ebay after a long search for a good fast cheap portrait lens. Review i found online showed it having good bokeh as well as being crazy sharp at f4 while a bit soft a f2.0 (not necessarily bad for portraits). It came pretty much new for about 110$. The focus ring is fairly tight (sticky?) apparently its oiled with tank grease, but i'm not sure if thats true....
First impression are that it is well built, being fairly heavy for its size, but that probably comes from the large amount of glass. Obviously being an m42 lens its all manual but i don't seem to have much problem finding focus. (find a af confirm adapter if your worried about focus). The lens has a preset aperture meaning that you set the aperture then there is a third ring that you can open up to full or back down to your preset aperture to allow for focusing with full aperture (yeah sounds funky but it works well). Also the aperture is (i think) 15 blades soo possibility for amazing bokeh.
Another review stated that it has flare problems so i got a lens hood for it but i have yet to see any problematic flaring.
Good shot of the adapter below:
Sooo some samples from my first test shoot (ducks cause they were at the nearby park, will do some portraits later) ALL AT F4.0
100% Crop of above
100% Crop of above (no i don't know why its sideways)
Keep in mind that the lighting was fairly harsh (mid day summer day sun) and i still haven't quite gotten the focusing down, so they will get sharper. I'll post some from f2.0 later when i take some portraits.
So in conclusion do i like this lens... YES, if you don't mind manual focus and aperture control then m42 mount lenses are great (and so apparently are some Russian lenses) (no i'm not a spokesperson for people selling these lenses either i'm just very excited by this find.)