On 6/14/2018 1:48 PM, Jim-P wrote:
In film cameras, ISO referrs to the sensitivity to light of the emulsion.
Manufacturers formulate different film emulsions with different
sensitivites tarding increased grain with increased ISO speed.

In a digital camera, presumably the sensor does not adjust itself to have
greater sensitivity. Or does it?

So what is happening in a digital camera when I choose a greater ISO
setting? Is more amplification being used?

I tried to understand this page but it got far too technical....

https://photography.tutsplus.com/art...n--photo-11963


I am going to try to give you a simplified, non-technical explanation.
As with most generalities it is not 100% technically accurate, but
should serve as a guideline.
ISO is a measurement of the light sensitivity of the sensor. Digital ISO
is adjustable in many cameras. And yes, it is a matter of adjusting the
amplification. If you are using a wider lens opening, and slower shutter
speed, you will be able to use a lower ISO.
Digital noise is one of the undesired artifacts in the image. Higher ISO
will result in more digital noise, and lessor image quality. Many of the
newer high quality sensors are designed to work at a higher ISO, with
less noticeable noise, and reduction in image quality.
There are some of us here who do not object to noise, while others have
serious objections. The point at which noise becomes objectionable often
comes down to a matter of taste and personal preferences.

HTH

BTW: I will not get involved in a war over technicalities. There may be
some who will nitpick my simplified explanation. If you have a specific
question, i will be happy to either answer it, or give you a reference.

--
PeterN