This is not a range finder lens. The 135 STF is a legendary Minolta lens that got carried over to the Sony line up. It is probably the only A mount lens I wanted to have, but could not justify the logic of buying a Sony DSLR (the A900 at the time) just to use this one lens. The answer comes out when the NEX mirrorless is introduced by Sony. I bought this lens along with the NEX 3. Three years later, now it is finally matched with a full frame sensor.