Keep the noise down

Minimizing and reducing any noise in your photos

Noise appears in photos taken at high ISO settings. Modern cameras offer ever increasing ISO values, and ISO1600 is much better than when digital EOS cameras were in their infancy. Noise due to ISO exists throughout an image, but is more noticeable in the shadows and dark areas of low light images.

To combat noise there are a range of solutions available. If you shoot JPEG images, then you can use the camera’s high ISO noise reduction function. This reduces the noise, but often leaves the images looking soft and lacking in high frequency details. For Raw shooters, noise reduction can be adjusted when processing the images. Canon’s DPP software will adjust the noise reduction settings depending on the ISO in use and the camera model, which it reads from the image file. You can change the noise reduction settings with the sliders in DPP during post-production.

When shooting long exposures, there is a build-up of noise in the image. However, the position, and amount of noise, is very consistent from one image to the next, if the ISO is the same and the temperature of the camera is similar. Advancement in sensor manufacturing technology has reduced the existence of long exposure noise, but not eliminated it. Your camera will have a long exposure noise reduction setting. This allows the camera to take a second dark frame exposure with the shutter curtains closed straight after your main picture is captured. This second dark frame has the same exposure duration, and then the camera processes the captured image and the dark frame to reduce noise.

Multi-shot noise reduction capability is a recent feature. It works by taking four captures, then processing the four images to create a single, noise reduced image. There are two main limitations to multi-shot noise reduction; it can only be used when shooting in JPEG, and the subject must be static while the four frames are captured. I think a sharp image with a little noise, is better than a blurred image with less noise.

Taken on a dark evening, the clouds were not visible to the naked eye, yet at ISO25,600 the camera captures this riverside scene full of detail

at ISO40,000 this EOS-1D X Mark II image has visible noise, but can be reduced in DPP