Quote Originally Posted by Abhinow79


Meanwhile I had no idea that 1.6
bodies also decreases the aperture width of the lenses. I thought that
a f 2.0 lens would be constant f 2.0 on both cropped and full frame
body!


50mm on XT and 50mm on full frame result in very differnet images. The angle of view is very different. To get the same angle of view requires using 80mm on full frame. So it can be said that 50mm on XT is equivalent to 80mm on full frame.


f/5.6 on XT and f/5.6 on full frame result in very different images. The depth of field, diffraction, and total amount of light is very different. To get the same DOF, diffraction, and light requires using f/9 on full frame. So it can be said that f/5.6 on XT is equivalent to f/9 on full frame.


There is a thread going on about this right now:


Crop factor and f/stop