>Dirk: Please explain diffraction degradation in laymen's terms.
>
>RonS
I can't really explain it in any terms really. My understanding is that
diffraction is a function of the diameter of the aperture and the wavelength
of light. As the aperture is stopped down to a smaller diameter, the light
tends to bend around the edge of the opening, rather than passing through
uneffected. The aperture begins to function like a lens or a prism in other
words. Since you have to stop down further with longer focal length lenses
to achieve the same depth of field, sharpness (resolution) becomes less than
with shorter focal length lenses. This tends to negate the advantages of the
larger film format. However, the effect is not so bad if you are just
enlarging the negative to the same print size, since you enlarge larger
negatives less than smaller ones in that case. But, as was mentioned earlier
by another list member, there are other effects at work here that apparently
tend to make larger formats better than smaller ones. I don't pretend to be
an expert, and I'm sure I've already said too much for my limited
understanding.
Be seeing you.
Dirk Wright
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