Andre's Blog
Perfection is when there is nothing left to take away
Crop factor vs. magnification

Crop factor is a term associated with sensors smaller than the standard 35mm film frame, which is commonly misunderstood, even by people who write for respectable sites, such as Luminous Landscape. Consider the Understanding the DSLR Magnification Factor article written by Nick Rains in 2002. In this article Nick writes:

‘Crop’ is a fairly good term – the imaging area is physically smaller. Less of the image circle projected by the lens is used, therefore it is a crop. The image remains the same size at the film plane for a given lens and subject distance – it is in no way magnified. It does, however, take up a larger proportion of the (smaller) frame and so it is easy to see why some people call it a magnifying effect.