Originally Posted by Speedfreak
But as soon as a scanner is involved film loses. There is hardly any scanner on the market that reaches the "latitude" of an entry level dslr.
This just plainly isn't true there are plenty of scanners that can do that. If I have a wider scale single negative then I can make one scan for the shadows, one for the highlights and one for the mid tones–then merge them in PS.
The D-max the scanner is capable of set a ceiling in that respect normally negative film would have a D-max of less than 2-2.5 slides are higher but have lower DR.
It's not a that hard to take a SBR of 10,000:1 and with the right film (say HP5) judicious metering, increased exposure and a compensating development record the whole scene in order to present a printable negative which will also be easy to scan.
In fact scanning and printing gives a wider range than traditional printing where you need to be an expert to get more than 10 zones.
So film capture allows for compression to take place in the highlight shoulder region of the curve at capture, that compression could separate a diffuse highlight from a specular one where the difference (SBR) could be five stops in the actual scene, but the print their relationship may be less than one.
Its a non linear relationship that the eye finds an acceptable illusion of reality.