You\'ll find that the increase of quality has to do, mostly, with pixel pitch and resolving power. However, you have to bear in mind that if you were to take a picture with a crop body at a certain focal length, then take a picture with a full frame body at the same focal length WITHOUT recomposing, then crop the full frame picture to match the crop picture, the quality will be about the same.
However, the quality difference is not a leap faith. Whenever you increase the size of your format (in this case, CMOS sensor) quality is always increased. The reasons are two fold:
A) Pixel pitch - Larger pixels = less noise. Less noise = greater sharpness. This point becomes moot when the full frame camera\'s pixel pitch approaches that of a crop body.
B) Glass resolving power. This is the biggest issue. The glass we\'re using now in lenses is pretty darn good, but the resolving power is still not high enough for the crop sensors to get lots of minute detail at their very small pixel pitch, which is why pixel peeping on crop bodies will yield a bit of smearing, regardless of lens used. As you increase the format, the resolving power of the lens because less important as you don\'t need it the resolution be nearly as fine for the image to be clear. The difference in format, of course, requires you to compose differently in order to achieve the same framing. But if you\'re projecting a picture of a house on to a small format and then the same frame house on to a larger format, the resolving power of the lens attached to the smaller format will need to be much higher than that of the larger format to achieve the same sharpness.
As an aside, the DoF issue is not due to the larger sensor, but the requirement to recompose to achieve the same framing.
Jun 10, 2009 at 11:52 AM
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