The ISO setting on your camera controls how sensitive it is to the surrounding light, and together with the aperture value and shutter speed it determines the exposure of your images. That is how light or dark they are or how much atmosphere they show.
Most cameras have an ISO range of at least 100-6400; the higher the number, the more sensitive to light the camera becomes.
Increasing the ISO to a higher number setting enables you to use a faster shutter speed at a given aperture, and there are lots of situations where this is useful.
If you are shooting in low light, increasing the shutter speed will help to minimise camera shake, and you’ll also need a fast shutter speed to capture for example fast-moving subjects like sports or wildlife. But this may result in your pictures coming out too dark.
Increasing the ISO to these higher numbers allows you to use faster shutter speeds and/or to use a smaller aperture settings (at a given shutter speed), which you’ll need to do if you’re shooting landscapes and want a deep depth of field (focus) to keep everything sharp.
There is a trade-off for increasing your ISO setting however, and that’s a reduction in image quality. Using a high ISO will introduce image noise, which can make your shots look grainy.
That said, newer cameras do a pretty good job of controlling noise at these higher ISO settings.
is a writer and photographer; he is also a lecturer in higher education and runs a number of private, retreats, courses and workshops...
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