Canon 0304B001 User Manual - Page 167

3 Custom Function Settings C.Fn-15 Shutter curtain synchronization 0: 1st-curtain synchronization 1: 2nd-curtain synchronization By using a slow sync speed, you can create a light trail following a moving subject. The flash fires right before the shutter closes. This Custom Function can be used to obtain 2nd-curtain sync effects even with EX-series Speedlites which do not have this feature. If an EX-series Speedlite having this feature is set for 2nd-curtain sync, it will override this Custom Function. C.Fn-16 Safety shift in Av or Tv Safety shift can be set for the shutter-priority AE and aperture-priority AE modes. 0: Disable 1: Enable If the subject's brightness changes suddenly and the current shutter-priority AE or aperture-priority AE setting becomes unsuitable, the shutter speed or aperture is shifted to obtain a suitable exposure automatically. C.Fn-17 AF point activation area 0: Single AF point 1: Expand (TTL. of 7 AF points) The AF point activation area expands by one point all around the manuallyselected AF point. A total of 7 AF points become active. This setting is effective for when only one manually-selected AF point is unable to focus track a subject moving erratically. 2: Automatic expand (max. 13) The camera automatically sets the AF point activation area to 7 or 13 points to suit the lens focal length and AF mode.This is effective when the subjectís movement is unpredictable. The AF point activation area centers on the selected AF point. Therefore, if a peripheral AF point is selected, the AF point activation area will be smaller as shown below. 7-point activation area 13-point activation area Selected AF point Activation area Setting C.Fn-13 will also expand the AF point activation area. 167