When to change sensitivity

There are times when pushing the ISO higher is not just unavoidable, but recommended

Your camera’s ISO menu offers a selection of sensitivities which will be displayed either in full or third-stop increments, along with an Auto ISO option where the camera does the selecting for you. There may also be a range of expanded settings – if these are greyed out (as the screen above), you’ll need to unlock them in the main menu. Choose higher numbers to increase the sensitivity, which in turn will allow you to use a faster shutter speed. There are numerous reasons for wanting to do this – here are some examples…

Avoiding camera shake

The chance of a photo becoming blurred through camera shake increases if the shutter speed drops below 1/focal length (for example, slower than 1/100 sec for an equivalent 100mm focal length). Set a higher ISO to access faster shutter speeds.

Capturing fine detail

If you want to record the maximum amount of detail, use the lowest ISO possible. Noise and noise reduction processing will reduce the amount of fine detail visible in a picture.

Shooting indoors/in low light

If you’re not using a tripod, increase the ISO to avoid blurred photos as a result of camera shake or subject movement. Make sure you make a good exposure too: if the image is dark and you brighten it later in software, you’ll exacerbate image noise.

Freezing moving subjects

If you’re photographing action with a ‘slow’ lens (one that has a relatively small maximum aperture, such as f/5.6 or f/6.3), then you might not be able to get a fast enough shutter speed for sharp pictures, even in good light, without increasing the ISO.

Using long exposures

To extend an exposure for creative effect, you’ll need to use a slow shutter speed. You can achieve this be setting the lowest ISO available and selecting a small aperture.