wdross wrote:
Pixel sizes change with format. That is only the first difference of many. Also, just because a 24.2mp APS-C would have the same density as a 36.3mm full frame sensor on a "pixels per square inch" basis, even with same size pixels, it would not make them equal except for density per square inch. They would not be equal in DOF, resolution, or angle of view. Any change in format will creat changes and differences between the two formats even if some items and things are kept the same.
I am having a hard time understanding the crop ratio as you have explained it, angle of view is linear, I can understand that, for instance on a Canon 1.6 APS-C camera a 10mm lens is the same as a 16mm lens, but when it comes to an image's area everything is different, to enlarge an image from 10" to 20" in width, it will require 4X the print area 4 full original images will fit in the enlarged image, 2 across and 2 down, it is the same with the sensor, it is measured in area, not linear like the angle of view. As far as depth of field is concerned it is different because the angle of view, to get a picture of a face framed the same size using a 50mm lens on a cropped camera and a full frame camera you will have to get closer to the subject with the full frame making the DOF of the image smaller. I guess what I am having the biggest problem with in the above statement is that you have stated that a 24.2mp APS-C would have the same pixel density as a 36.3 full frame on a "pixels per square inch" I just don't see how that could be true when the area of the full frame sensor is more than twice the size of the crop camera sensor.