Understanding what ISO does

Camera Tips – Understanding what ISO does

ISO is one of the 3 cornerstones in photography, the other 2 being Shutter and Aperture.

In very simple terms, imagine a dark room with lamps, the more lamps you turn on the brighter the room becomes, this is how ISO works, the higher ISO number (the more lamps turned on) the brighter your shots become.

As you increase the ISO, the sensor becomes more sensitive to light. Each time you double your ISO number (say from ISO400 to ISO800), the sensor becomes twice as sensitive to the available light.

In my camera training workshops I use the analogy that ISO is like salt in your cooking, add too little and it has no effect, add too much and it ruins the meal. Adding too much ISO introduces a lot of graininess and can ruin a shot so add just enough to get the job done. The best advice I can give is to keep your ISO down as far as the shot will allow.

In the 3 images below, shot in a dark hallway, I have set the Shutter speed to 1/80th and the Aperture to f4.5 and these won’t change. The only variable now is the ISO.

As I raise the ISO from 400 to 800 and then 1600 you can see the photograph of the clock go from dark and unusable to bright and just what I wanted.

If you find your shots are too dark try bumping the ISO up a little at a time. If that doesn’t work call me and I’ll help to get you sorted 07964 10 9 8 7 6