Originally posted by jusfun21 Well HCC, I know it is probably LBA because I can use the Tamron because on a APS-C sensor, 85mm is not 85mm but closer to 128 mm.
(sigh, not again...)
No, an 85mm lens is not a 128mm lens. It does not magically change size when put on a different camera. An 85mm lens is an 85mm lens, period. Cameras with different-size frames (film or digital) see different amounts of the projected image, that's all. A smaller frame crops more of the image. That's why a dSLR that isn't FF is called a crop-sensor. On any camera, an 85mm lens and a 90mm lens will have nearly identical FOV's. On your crop-sensor cam, that's around 20 degrees. On a FF cam, it's around 28 degrees.
EDIT: Oh wait, I was wrong! I just tested this -- I put my big fat Jupiter-9 85/2 onto my K20D... and it started GROWING!! It got LONGER! And HARDER! And it's STAYING UP!! It's like VIAGRA FOR LENSES!! If I can sell this, I'LL BE RICH!!! Ooh ooh!! [/me gets all excited, must take cold shower]