Canon EOS Rebel T2i EOS REBEL T2i / EOS 550D Instruction Manual - Page 220

Troubleshooting Guide The card cannot be used. If a card error message is displayed, see page 42 or 224. The maximum burst during continuous shooting is lower. Set the [7 Custom Functions (C.Fn)] menu's [High ISO speed noise reduction] to [Standard], [Low], or [Disable]. If it is set to [Strong], the maximum burst during continuous shooting will greatly decrease (p.193). If you shoot something that has fine detail (field of grass, etc.), the file size will be larger and the actual maximum burst might be lower than the number mentioned on page 72. ISO 100 cannot be set. Under the [7 Custom Functions (C.Fn)] menu, if [Highlight tone priority] is set to [Enable], ISO 100 cannot be set. When [Highlight tone priority] is set to [Disable], ISO 100 can be set (p.194). This also applies to movie shooting (p.134). The Auto Lighting Optimizer cannot be set. Under the [7 Custom Functions (C.Fn)] menu, if [Highlight tone priority] is set to [Enable], the Auto Lighting Optimizer cannot be set. When [Highlight tone priority] is set to [Disable], then the Auto Lighting Optimizer can be set (p.194). This also applies to movie shooting (p.134). When I use the mode with flash, the shutter speed becomes slow. If you shoot at night when the background is dark, the shutter speed becomes slow automatically (slow-sync shooting) so that both the subject and background are properly exposed. If you do not want a slow shutter speed to be set, set the [7 Custom Functions (C.Fn)] menu's [Flash sync. speed in Av mode] to 1 or 2 (p.192). 220