The FX lens's image circle covers the 36mm x 24mm of the FX sensor. The DX lens's image circle covers the 24mm x 18mm of the DX sensor.i just ordered this from Amazon..
50mm
my D5100 is listed as a DX type camera but the lens is a FX type. Amazon seems to think it will work just fine with my camera but the i wanted to verify that as well as to ask what is the difference between DX and FX?
thx.. am excited about this purchase - a very good prime lens for little money and the first i bought that didn't come with the camera. next up, the 18-140mm..The FX lens's image circle covers the 36mm x 24mm of the FX sensor. The DX lens's image circle covers the 24mm x 18mm of the DX sensor.
All FX lenses work perfectly with DX sensors. In contrast the image circle of a DX lense is smaller than the FX sensor, so you will get vignetting - light fall off at the corners if you use the DX lense with FX sensor. How much depends on the lense and the focal length.