Deeper pixels needed

Glenn Reynolds, assorted Slashdotters and Peter Lewis at Fortune are speculating on whether Ansel Adams would have used digital cameras.



As I worked on the first official release of Ansel Adams images in digital form - the Ansel Adams screensaver - I feel somewhat qualified to pontificate on this.



What everyone is missing is that it is not a question of resolution, but of dynamic range.

With film the issue is blurred by questions of grain, but with digital the problem is which image format to use.



TIFF supports more than 8-bits per channel, but JPEG does not, nor do most computer displays. Most digital cameras only generate 8-bits per channel of dynamic range, and are still competing on resolution.

On the other hand, even the $30 scanners do 12-bits per channel these days, and 14-bits per channel (42-bit) are only about $50.



I expect that digital cameras will pick up on this soon, but we'll need a file-format change (and possibly a better transient storage device than flash memory) and new low-cost software to make it mainstream. Ironically, all the sophisticated exposure calculation that makes many digital cameras too slow to use for action snapshots could be reduced if they upped the dynamic range a few stops.



If you want to see what kinds of dynamic range digital photography is really capable of, have a look at the Hubble images, where every photon is carefully counted.