Reduce noise at high iso settings - Tips for photographer

Shooting indoor sports action using a fast shutter speed, old, gloomy   churches without flash or bright landscapes where you want to slow  down  the shutter speed to capture movement are just some of the many situations where you will need an extreme ISO to get better results.

ISO  denotes how sensitive an image sensor is. Any change from the   manufacturer’s native ISO (the lowest default, which produces the   optimum image quality) will have some form of electrical signal   modification that results in noise.

Most DSLRs have a native ISO  of around 100 or 200; beyond that, at  the extreme low end of the range, quality isn’t improved. However, some  manufacturers offer lower ISO  values in the menu, such as ISO 50. Others  use a decimalised f-stop  value to indicate when it falls below the  native ISO.

Both are great for using wide apertures (for more on apertures, download our free f-stop chart for understanding aperture) or long shutter speeds in bright lighting conditions.

When  using extreme ISO values above the highest setting, most cameras  share  the prefix letter H followed by an f-stop value to indicate when  the  ISO is being ‘pushed’ to the limit. Such images can be very noisy,  but will allow you to carry on shooting in very dark conditions.

 Step 1: Go manual
Turn off any ISO sensitivity control modes that automatically select a suitable ISO depending on the shutter speed and aperture. You should   also switch off any Scene modes and select either Manual or 
a   semi-automatic exposure mode.

Step 2: Select the ISO
Most recent cameras will have a dedicated ISO button that’s located on the camera body. Locate the button on your camera and have a scroll   through the ISO values from one end to the other to see if you have the L or H prefix.

Step 3: Reduce the noise
Any amplification or reduction of the electrical signal that’s been   produced by light falling on the sensor’s CCD will suffer from noise. Dig into your DSLR’s menu and turn on any in-camera noise reduction for the very best results.