In hearing many things about “how much detail is enough?” I find a certain irony in hearing that digital is “good enough” and top quality film has “too much extraneous information” from the same people (not necessarily on this list) who would rather die than be caught with a third-party lens on their camera. I mean, why buy a lens that will resolve to 120 lines per mm if the medium that you are capturing to will not resolve 1/10 of that? What is the advantage of a Minolta G prime lens over a Cosina 28-300 zoom if the medium being recorded is a CCD array, complet with noise, at 1024×1200 pixels? I exaggerate a bit, but it makes you wonder…
I have read (I forget the source) that the maximum amount of data on the most fine grained film that a scanner can caputure is about 6000 dpi. Beyond that you are resolving grain. Some exceptions are good to over twice that (12,000dpi for Technical Pan). This would result in files of 600 MB per image for most films, and 2.4 GB file for one Technical Pan frame. So when you shoot a roll of 36 exposures of Kodak Gold, you have recorded 21.6 Gigabytes of potentially digital information. Leaving aside all questions of how useful this might be, suffice it to say that digital cameras have a long way to go before they match the potential inherent in film. If you have ever shot 20 rolls of film in one day, ask yourself where 432 Gigabytes (almost half a terabyte) will go in your camera bag.
Note: Since I wrote this in 2001, digital cameras have made considerable progress. My current take is that a 6MP digital camera can match most the quality of equivalent 35mm film cameras under most condtions. Exceptions might be: using Velvia or Technical Pan while shooting tripod mounted.