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0 2 . U N D E R S TA N D I N G E X P O S U R E
ISO THE SIMPLEST OF THE THREE SIDES of the exposure triangle is ISO. You can think of ISO as the sensitivity of the digital sensor (although it is a lot more complicated than that). A high ISO (around 1600) can “gather” light more quickly in darker situations, whereas a low ISO works in very bright situations where you don’t need so much light to be “collected” by the sensor. Unlike aperture (which affects depth of field) and shutter speed (which records any movement that occurs while your shutter is open), the only real effect that ISO has on your images is to brighten or darken them overall. Just keep in mind that the higher the ISO, the more noise or grain you will have in your final image.
ISO SCALE Grain starts showing up Collects less light Less image noise/grain
100
200
400
800
1,600
3,200 6,400 12,800 25,600
1-Stop Increases in Exposure 1-Stop Decreases in Exposure
PRO TIP IT IS BEST TO PHOTOGRAPH at the lowest ISO possible while keeping your shutter speed reasonable for hand held photography (unless you are using a tripod, of course) and keep your aperture as low (wide) as you choose for the situation.
8
Collects more light More image noise/grain
