Fred Briggs

I was referring to the original comment, not your reply - specifically where it says: "correctly exposing the same image with 4 extra stops of 'iso' "

I know the original comment does not...

You are not correctly exposing the image if you are using 4 stops of ISO adjustment. Given the same aperture and shutter settings both shots are equally underexposed with the sensor receiving...

Further to my previous comment, I guess there can be a situation where you might regard an ISO setting as leading to lower exposure, but I think it is still an indirect relationship. If you need a...

It is hiss from an audio amp rather than hum which is more analogous to the noise found in digital photos. However, exposure v ISO setting is not a causal relationship, as you imply, when you say...