Attributed to Erwin Puts:
“A most interesting phenomenon became evident with these side-by-side shots. The Skopar gives images with a grainier pattern and with grain clumps that are rougher than those in images made with Leica lenses. This is caused by the lower aberration content of the Skopar lens. When aberrations are abundant the light rays emanating from a point source of light do not converge to a point in the image but have a more random pattern around the central core. These more widely spread rays energize more silver grains around the center spot and they do so randomly. The result is a rough clumping. Modern Leica lenses produce a smooth pattern of very tightly contained clumps of grains, which helps to preserve the rendition of very fine details and the smooth gradation of fine light modulations.”
I'm sorry, this just sounds like obsfucation trying to substantiate a non-existant fact. How many of our photos contain so many point sources of light that this will make a noticeable difference? That is assuming it is in fact true. If there aren't many point sources of light, how will this condition manifest itself?
EDIT: I guess since I don't own any of the mentioned lenses, I really shouldn't comment anyway.