I think so. I don't mean always, but both hole diameter and diffraction
are parts of the pallette, so to speak.
Also, diffraction can appear to be simple diffusion, but it also produces
light sprays (there's an example on my webpage at
http://www.halcyon.com/cif/Kingfisher/Photo/Pinhole/pIndex.html). It
looks totally different in black and white vs. color because the
different colors diffract differently, just as they refract differently.
Part of my interest in the subtleties of this (generally considered to
be) defect in the image may stem from my interest in all kinds of optical
abberations. I am nearsighted and have astigmatism, and like Monet, I
find the world I see uncorrected quite interesting and exciting. (Monet,
I understand, refused correction. I don't go that far.) I often use
optics which are uncorrected or minimally corrected; stuff I get from
Edmund Scientific. I have a box of old Optometrists' diopters which I
can stack on the front end of a speed graphic, including a full set of
"astigmats".
Not everybody's cup of tea, I'm sure. But it's fun.
Larry Bullis
Skagit Valley College