On Tue, Dec 14, 2010 at 7:51 PM, Larry Colen <[email protected]> wrote:
> Let's say that we're shooting through a crappy lens, or a dirty window, or > we're taking a picture of a greycard on a beige sedan on a foggy day. There > is plenty of light, but there is only 5 stops of dynamic range in the scene > that we're shooting. I.e. all of the values fall between 2048 and 2080 mV > at base ISO, or ETTR 4063 to 4095mV which get represented by the values > 2048-2080 (or 4063-4095). You lost me here. If there's 5 stops of scene dynamic range, the low and high pixel voltages should differ by a factor of 32; for example, 64-2048 mV. I think what you're trying to do, specifically, is reduce quantization noise--the noise caused by rounding to the nearest bit--by allocating your whole 12-bit dynamic range only to whatever the scene dynamic range is, without loss. My thinking is that that, especially if you "expose to the right", quantization noise should be smaller than other sources of noise, such as photon shot noise and amplifier read noise. I don't, however, have figures for consumer sensors to back up this intuition. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
