Given that the sensors in DSLR's are not full frame and magnify by 1.5x, is this good? I was thinking that it would be a good idea to get a DSLR, and for portraits, get a 50mm 1.8 lens, and then with the smaller sensor, it would be like a 75mm 1.8 lens, which would cost a lot more money. Or getting a 300mm f/4 lens, and then the magnification would raise it to 450mm f/4. The only downside is the wide angle end, but already, Nikon has made a ful frame fisheye for DSLR's. Can anyone elaborate or clear up any misconceptions. I know there has to be a catch somewhere.