Canon EOS R6 Advanced User Guide - Page 204

High ISO Speed Noise Reduction You can reduce the image noise generated. This function is especially effective when shooting at high ISO speeds. When shooting at low ISO speeds, the noise in the darker parts of the image (shadow areas) can further be reduced. 1. Select [ : High ISO speed NR]. 2. Set the level. Low, Standard, High The camera applies an amount of noise reduction corresponding to your specified level. Multi Shot Noise Reduction Applies noise reduction with higher image quality than [High]. For a single photo, four shots are taken continuously and aligned and merged automatically into a single JPEG image. Note that [Multi Shot Noise Reduction] is not available with image quality set to RAW or RAW+JPEG. 204