I was talking to a friend yesterday when she asked what’s with ISO?
ISO relates to the sensitivity of the sensor in digital cameras.
It replaces the old ASA settings we used when we were shooting film.
Back in the film days photographers shot film with the lowest ASA possible for the shot.
The original Kodachrome had an ASA of 10! Film with an ASA of 10 was capable of producing a nearly grainless image.
In comparison today’s digital cameras have sensors which can produce the same nearly grainless image (with some help from photo editing software) with ISOs of 1,600 and higher.
ISO and ASA numbers are directly comparable.
When it came to film you were stuck shooting at the same ASA setting for every frame on the roll. With digital sensors we can change the ISO for every individual image. But the same recommendation to use the lowest ISO possible for the shot still applies if you are looking for grainless images. Digital cameras are so good at shooting virtually perfect images that there is software you can buy which will introduce a grainy look.
That’s what’s with ISO!