On 18 Oct 2002 at 12:28, Rob Brigham wrote: > To get lower ISO, I guess they need to > actually reduce the sensitivity of the sensors as the shutter is going > to be open longer and they don't want to 'burn out' the sensors - I > don't know if they do this by sampling (eg 100ISO = 1second shutter, > 200ISO = 2 second shutter but the sensor takes 2 images in this time and > averages them down?) or by reducing the current or something? I don't > think low ISO is so much a quality issue as much as a fundamental > technical problem.
I think that you'll find that the lowest ISO of the sensor is it's optimum sensitivity, at that point the noise is lowest and the saturation is highest. As the effective ISO is increased above this optimum you end up with a higher level of noise and earlier clipping of the brightest areas. So really unless there is a way to dynamically manage the sensitivity (saturation) of the actual sensors (not the signal amplifiers) I expect that as the sensitivities increase we'll have to resort to ND filters to peel back the effective ISO. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
