Sport photography: noise reduction in post-processing

Sports photography often requires very fast shutter speeds in order to freeze the action. In my experience, a minimum of 1/800 sec is required for basketball or soccer. My typical setting, which I save as a custom function in the camera is 1/1000 sec. Since lighting is often quite dim, particularly during indoor events or night games, fast shutter speeds require very high ISO settings, even with “fast” lenses (i.e. lenses that have large maximum aperture). As a result, the images become quite noisy, even when shot with state-of-the-art cameras, such as Canon EOS 5D Mark III or Canon EOS-1D X (in the Nikon world, there are counterparts such as Nikon D800 and Nikon D4S).

Noise becomes more noticeable when viewed at high magnification as random variations in brightness and colour between neighbouring pixels. These variations can be smoothed out in post-processing using fairly sophisticated algorithms implemented in various image-editing software. However, ultimately, this noise reduction causes loss of detail, which appears as lack of sharpness.

The good news is that in sports photography, relatively high levels of noise are considered acceptable. In fact, certain amount of noise adds character to the photo and conveys the sense of extreme effort exerted by the athletes.

Also, noise reduction is not nearly as destructive to the sharpness of the photo if the image is down-sampled (reduced in size) to be shown as a thumbnail on screen, for example. The counter-intuitive fact is that when the size (in pixels) of an image is reduced, the apparent sharpness is increased. This is because the small details that are lost due to noise reduction processing would not be visible anyway in the small image, so it appears both sharp and with low noise. The same is not true about the noise level, however. When the image size is reduced, the apparent noise is at best appears the same and often looks more pronounced than in the original, high-resolution photo.

Here are my typical strategy for noise reduction in Adobe Photoshop Lightroom, where I do most my post-processing. The Noise Reduction panel of the Develop module offers separate control of two main types of noise: Luminance and Color. Each of those has additional aspects, which can also be controlled separately (detail and contrast for Luminance and detail and smoothness for Color), but I almost never use them. I find the colour noise more unpleasant than the luminance noise, but it is also better controlled by the camera, so I rarely have to correct for it. I only work with Luminance slider for most of my photos.

• If the noise level is relatively low, I find that Luminance settings between 0 and 10 (in some arbitrary units used by Lightroom – they are really just relative indicators of the amount of noise reduction applied) do not cause visible loss of sharpness.
• If the noise is extreme, I set Luminance to around 30 and sometimes up to 50. Above that, the loss of detail is quite severe, and would be noticeable if the image is reduced in size.