Canon eos rebel T2i - Manual (Page 220)

Troubleshooting Guide
220
If a card error message is displayed, see page 42 or 224.
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.
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).
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).
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).
The card cannot be used.
The maximum burst during continuous shooting is lower.
ISO 100 cannot be set.
The Auto Lighting Optimizer cannot be set.
When I use the <f> mode with flash, the shutter speed
becomes slow.
COP
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