I have it understood that the DX captor brings a 1.5x factor applied to the framing of the equivalent in mm of lenses rated in terms of 35mm film. Doesn't sound that clear... That is a 50mm lens will render an image in a frame equivalent to that of a 75 mm. I would like to know what is the math behind that could also be applied to calculate the transformation when applying a crop to an existing image. I would like to express that in terms of pixels. I'm trying to figure out how this would translate if I would crop a 10.2 mp image from the coming D200 to one that has 6.1, like the D100 or D70 have. From Tom Hogan's site, I read concerning the D2x that it has: " A high-speed crop mode with a reduced angle of view of 2x from full frame (as opposed to the usual 1.5x) and reduced number of pixels (6.9mp from 12.2)." 6.9/12.2 = 0.57. Is it this .57 that is added to the 1.5 x factor to attain the 2x or so ? If I will extract a 6.1 mp image from a 10.2 delivered in the D200, it would bring an additional factor of 6.1/10.2 = 0.6, thus having the framing factor of 2.1x. That would mean that a 300mm shot in 10.2 mp but cropped to about 6 (with a resolution equal to that of the D100 or D70) would give a framing close to that of a 600 mm on a standard 35mm camera. Is this pure nonsense or what ?