This is a compact wide angle lens designed for M39 (LTM) mount. I used a LTM-to-M mount adapter and then a M-to-NEX mount adapter to use in on my NEX-3. I enjoyed shooting landscapes with it. There is little difficulty in getting everything in focus when set to f5.6 or f8.0.
Pros: small size, reasonably priced, sharp, little distortion
Cons: corner smearing/colour shift on NEX-3/5, no filter thread
Click here to view the photos taken with this lens on the NEX-3.