Canon EOS Rebel T3i EOS REBEL T3i / EOS 600D Instruction Manual - Page 252

3 Custom Function SettingsN Custom Functions are organized into four groups based on the function type: C.Fn I: Exposure, C.Fn II: Image, C.Fn III: Autofocus/Drive, C.Fn IV: Operation/Others. C.Fn I: Exposure C.Fn-1 Exposure level increments 0: 1/3-stop 1: 1/2-stop Sets 1/2-stop increments for the shutter speed, aperture, exposure compensation, AEB, flash exposure compensation, etc. Effective when you prefer to control the exposure in less fine increments than 1/3-stop increments. With setting 1, the exposure level will be displayed in the viewfinder and on the LCD monitor as shown below. C.Fn-2 ISO expansion 0: Off 1: On For the ISO speed, "H" (equivalent to ISO 12800) will be selectable. Note that if [C.Fn-6: Highlight tone priority] has been set to [1: Enable], "H" cannot be set. C.Fn-3 Flash sync. speed in Av (Aperture-priority AE) mode When you use flash in the aperture-priority AE mode (Av), you can set the flash sync speed. 0: Auto The flash sync speed is set automatically within a range of 1/200 sec. to 30 sec. to suit the scene's brightness. With an external Speedlite, highspeed sync is also possible. 1: 1/200-1/60 sec. auto Prevents a slow shutter speed from being set in low-light conditions. It is effective for preventing subject blur and camera shake. However, while the subject will be properly exposed with the flash, the background may come out dark. 252