We have audience asking if we'd do a noise reduction compare on the Osmo Action 4 camera, and to satisfy our own curiosity, we decided to perform the test. We ran the camera in a low light setting, starting at ISO12800 with most obvious sensor noise, while trying to keep everything as consistent as possible. 4K25P, 3500K Colour Temp, 1/50 shutter, sharpness at -2, and started to vary the ISO and Noise Reduction settings. We observed that there is significant jump between noise levels at NR-2 and NR-1 custom settings. Between NR-1, NR 0 and NR+1, its hard to discern the difference, but we can subtly tell that it looks as if the background have been frozen like a still static image. Its akin to adjusting bitrate on streaming or increasing the temporal compression rate. The subtle details in the flickering of light in the background is gone. Depending on ISO, we'll be likely to tweak and keep our custom settings to Noise Reduction -1 or 0 after this test & review.