Canon EOS50D EOS 50D Instruction Manual - Page 176

3 Custom Function SettingsN C.Fn II: Image C.Fn II -1 Long exposure noise reduction 0: Off 1: Auto For 1 sec. or longer exposures, noise reduction is performed automatically if noise typical of long exposures is detected. This [Auto] setting is effective in most cases. 2: On Noise reduction is performed for all exposures of 1 sec. or longer. The [On] setting may be effective for noise that cannot be detected or reduced with the [Auto] setting. After the picture is taken, the noise reduction process may take the same amount of time as the exposure. You cannot take another picture until the noise reduction process is completed. With setting 2, if a long exposure is made during Live View shooting, the LCD monitor will not display anything (no Live View image display) while noise reduction is applied. C.Fn II -2 High ISO speed noise reduction Reduces the noise generated in the image. Although noise reduction is applied at all ISO speeds, it is particularly effective at high ISO speeds. At low ISO speeds, the noise in the shadow areas is further reduced. Change the setting to suit the noise level. 0: Standard 1: Low 2: Strong 3: Disable With setting 2, the maximum burst for continuous shooting will decrease. 176