If a lens with an Image Stabilizer is attached to the EOS R and the Image Stabilizer (IS) switch is set to <ON>, the Image Stabilizer will operate at all times even if you do not press the shutter button halfway. The Image Stabilizer consumes battery pawer and may decrease the number of possible shots depending on the shooting conditions. When the Image Stablizer is no necessary, such as when shooting using a tripod, is is recommended that you set the IS switch to <OFF>.