CROP FACTOR
• Firstly the crop factor does not magnify the image in any way shape or form...
• Neither does it increase the focal length of the lens as some people seem to think...
• A 35mm film frame has an area of 36mm x 24mm (approx) as does a full frame sensor like the one in the Canon 5D and 1D's...
• The area covered by a 35mm film frame is indicated by the whole of the image on the right...
• The sensor in a Canon 20D is only 22.5mm x 15mm and the area covered with the same lens from the same position is indicated by the area within the dotted lines, this is the crop factor...
• As you will notice, the small sensor just crops the centre of the image giving an impression of being closer, not actually magnifying the image at all...
