On 5/5/2010 5:24 PM, Darren New wrote:

> Second, if you're talking about the ISO setting rather than the
> exposure, that's about how much you pre-bias the electrons in the
> sensor. Basically, you load up each pixel of the sensor with some
> electrons, and if light kicks out an electron, you add one to the
> intensity of the light there. Adding more electrons makes it easier to
> get kicked out.

I thought ISO essentially amplifier gain. e.g. A CCD (or CMOS) cell 
accululates a certain number of photons, which builds a potential, a 
fixed time later, after the exposure has been taken, some circuitry 
reads the potentials, send it through an amplifier (whose gain is set by 
the ISO setting in the camera's software) then to a DAC, and encoded in 
a file, rather than pre-charge the CCD....

-- 
~Mike

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