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Exposure : Aperture : Shutter Speed : ISO : Composition : White Balance : Flash : Mega pixels


ISO - Sensitivity setting

The ISO setting on a DSLR camera is how you control how sensitive it is to light.
(on a film camera the ISO has to be set to that of the film you are using)

The higher the ISO setting the more sensitive it is, so if you want to take shots in low light without flash you set your ISO to a higher setting, such as 1600 or 3200

The Lower the ISO setting the less sensitive it is to light, generally you use the lowest ISO setting you can work with i.e. 100 or 200.

Which ISO to choose and why

The other thing effected by the ISO setting is the size of the grain or pixillisation on the final image, this is most commonly referred to as ‘noise’.

The higher the ISO the higher the noise.

fairy ISO 1600 low light high noise ISO 1600
Examples of high noise

Here you can see that, although I have captured a nice image, it is to noisy to sell, or to blow up large. It will be okay for a small print or for online use, but you can see the price you pay for using a high ISO setting.


Using a higher ISO allows you to use higher shutter speeds, to capture action shots; or to use smaller apertures to increase the depth of field / amount in focus.

But you pay the price of increased noise.

Its worth noting that this is one area the big manufacturers are working hard on, so the newer DSLRs are substantially better at dealing with low light and have decreased the levels of ‘noise’ encountered.



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