What is Digital Camera ISO?

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Back in the old days when I had a film camera, ISO was to do with the film and it’s speed. I generally used ISO 100, 200 and 400, for bright conditions, cloudy conditions and all round conditions respectively.

It’s a little different with digital camera ISO

What is digital camera ISO?

Digital ISO gives an indication of the sensitivity of the camera’s image sensor (what would be a comparison to film).

And can be adjusted depending on how much light is entering the camera. Which sounds a little like EV compensation to me, but it isn’t!

The lower the camera’s ISO the better the image quality of the photographs.

The higher the ISO setting the more chance there is of the image having digital noise (depending on your image sensor).

So what is noise?

Briefly it occurs when the ISO has been set high and therefore the image sensor is very sensitive to the amount of light coming into the camera, but also sensitive to anything else as well. And that results in noise or ‘dots’ appearing in the image.

The size of the image sensor in your camera is directly related to it’s ISO speed range and how large it can be. It can go as low as 50 or up into the 1,000’s, each camera will have it’s own range. Point and shoots only have small sensors so a high ISO will cause noise. Where as DSLR camera’s have large sensors so noise is not so much of a problem and higher ISO’s can be achieved.

Why would I use it?

If you are in a low light situation where you want to take a picture but can’t get the right exposure because you can’t use a flash, then using a higher ISO to get the right exposure for the picture is the best option, and will let you take the picture.

This can increase the risk of noise in the image. But I would take the photograph anyway because you can use post production software to remove most of the noise afterwards.

Digital cameras will have an auto ISO setting as well, and the camera will automatically select a higher ISO when light conditions are low, but you may want to adjust this.

My Camera

My camera has an auto ISO setting and a choice of 100 and 200 ISO settings. So the auto setting will decide between the two in low light if I don’t choose one myself.

Mandy

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