Why "crop factor" is so pervasive

[dankearl]

I , too, am lost in the details here.
I just got the Nikon D800, which gives you 4 different crop modes.
Am I correct to assume that the crops are just in camera, in other words, other than the file size, should I
just take FX or full frame images and just crop them myself?
Am I going to get the same quality cropping after the fact than just taking the image in DX or 1.2 crop mode?
If that is the case, why aren't all camera's full frame?

[Michael Gerald-Yamasaki]

I just got the Nikon D800, which gives you 4 different crop modes.
Am I going to get the same quality cropping after the fact than just taking the image in DX or 1.2 crop mode?
If that is the case, why aren't all camera's full frame?

Yes, cropping to the DX or 1.2 fov in camera or cropping after the fact are equivalent.

There are cropped sensors for production cost considerations.

Cheers,

-Michael-