I know this sounds like a stuiped question but I have got to ask. The nikon D-300 has a 1.5 crop factor.Now is that only with a DX lens. Do you get the same 1.5 with an FX lens on a D-300. To appreciate the additional mm lens on a D-300 does it have to be a DX lens. Is using a FX lens on a D-300...