Completely off topic, since we're drifting there anyway, Loren Eiseley was another scientist with a strong artistic side. His essay, "How Flowers Changes the World," should be mandatory reading for any human being.
Drifting further off topic (why not?), for anyone who hasn't heard of him, check out the works of Ernst Haeckel
, especially Kunstformen der Natur
(Artforms of Nature). I wish I could take macro photos half or even 1/4 as good as his 120-year-old drawings.
Slightly back on-topic, when shooting film, it all depends on how slow film you use to take shots, how good your scanner is, etc. Lots of people making comparisons (not just here, but on the interwebs), are forgetting that they're scanning slides shot 30 years ago on glass that didn't have as fancy coatings as now (although some old lenses are sharper than current counterparts, i'm looking at you, Super Takumar 50/1.4 vs EF 50/1.4).
Aside: i've just thought of a test, seeing as I've got an EOS 3 now (now there's one way film beats digital, Eye control AF), and a roll of Velvia 50 lying around, i'll go ask my friend if he's bought his 5D3 yet and do a direct same-shot-same-lens comparison one day.
Anyway, let't think mathematically.
5D3 is 5760x3840 = 22.11 x10^6 pixels.
Let's scan a 135mm film to 4800dpi:
36/25.4*4800 = 6803x4535 = 30.85 x10^6 pixels.
OK, so scanning all but the finest-grained film is not going to give you the same sharpness as a D800. So let's downscale the scanned film a bit later on.
Now, as is my understanding, an iso100 film has the same grain size, whether it's deposited on a 135, 120, 4x5, or 8x10 negative. (if i'm wrong on that, better stop me here).
So let's scan in a 645 (cropped to 3:2 ratio) film, 56x37.3mm, at 4800dpi.
56/25.4*4800 = 10582x7055 = 74.65 x10^6 pixels.
OK, that's about what I was expecting (i was typing as I worked, so i'm reading the results now too).
Basically, scanning 135 film gives (near enough) equal to the best FF digital in terms of MP (D800), just as scanning 120 film gives equal to the best MF back (IQ180). That's assuming that scanning film to 4800dpi gives just as good results as the digital equivalent, which is a test for later. But the results should scale, if I can only scan a 135 Velvia 50 at 2400dpi (or more likely, to 4800dpi then downscale), I'll get 1/4 the res (7.5mp), and scanning 120 film to the same will give 18MP.
Anyway, that's just from an MP perspective. DR and colours is a whole different perspective, and we could go all day, but they're just not directly comparable (vinyl vs CDs vs MP3s anyone? or transistors vs tubes?).
The best thing about film is the non-linear response curve, so highlights don't get clipped as easily, even if you overexpose a bit too much (if you're good and process your own), you can recover a bit by underdeveloping. With digital, once the photon-bucket is filled, it's filled, no going back (although you can instantly see results and shoot again, another plus on digital). So there's never going to be a direct number-to-number comparison. Knowing your tool is more important than the tool itself in this case.
The best film will always beat the worst digital.
The best digital will always beat the worst film.
I think that's the only thing we can say with certainty...