ISO & pixels ..??

[mako]

Good Day,

I like to understand how ISO settings in digital photography create "noise" (or grain in film photography). Why high ISO settings would result to more noise?..(worse, why different digicams result in different noise levels at similar ISO settings?)

What I understand:
ISO is something like the measurement of light sensitivity - in film photography, the diff' ISO film causes grain difference. In digital photography, isn't grain - noise measured by pixels?

TIA - thanks in advance!

cheers! :)
S30 user..

[UKinNY]

Hi mako,

the basic reason for this is that the signal that the ccd gets needs to be boosted. The higher the ISO setting, the lower the signal the CCD gets. Whenever you boost a signal you also boost the noise. Now, special electronics can minimise the boosted noise, but not entirely.

see http://www.photocourse.com/01/01-02.htm for a far better explanation however

[mako]

Thanks UKinNY, for shedding some light onto the subject.

The link shared lead to an informative site - must visit!

Learnt some more & ensured me further why I paid premium for the 3 megapixel S30 cam, cos' of the ISO50 setting I wanted. :)

Mako
Singapore