Very interesting read at www.butzi.net/articles/5dprintsize.htm

The real difference between digital and film has more to do with the kind of image being captured and the degree of enlargement desired. Dependent somewhat on megapixels or negative size and film type, digital and film produce identical results as far as the human eye can detect up to some threshold of enlargement. That threshold varies a lot dependent on film speed, developer, digital sensor technology, lens quality and so forth. Above that threshold, a reasonably trained human eye begins to see the differences. In some cases digital will win, in other cases film will. The determining factor as to which will "win" is the image subject, not the technology:

In a nutshell, if your image has tiny tiny details, film will fake more of them as you make larger and larger prints, and the eye will be fooled into thinking there is more detail than there really is. Digital, on the other hand, will hold it's own until at some point the detail will disappear completely, disappointing the eye since where film grain will provide spurious but realistic looking detail, digital will show only empty (light or dark as the case may be.)

On the other hand, if your image is bold colors or patterns and has no intricate detail (e.g. clouds, sky, some kinds of landscape), film will begin to "fail" at larger prints due to the introduction of detail that the eye thinks should not be there. Digital, due to the sharp drop off point (he uses a term "Nyquist boundary"), the same areas will be pleasingly uniform rather than grained up. Same technical phenomena as above, but since the image is different, digital wins and film fails.

Does this make sense to you, it does to me.

Brandon
brandonsmithgallery.com