Canon eos rebel t1i - Manual (Page 204)

Troubleshooting Guide
204
Auto power off is in effect. If you do not want auto power off to take
effect, set [5 Auto power off] to [Off].
Even if [5 Auto power off] has been set to [Off], the LCD monitor will
still turn off after the camera is idle for 30 min. Press the <B>
button to turn on the LCD monitor.
The card is not properly inserted (p.31).
If the card is full, replace the card or delete unnecessary images to
make room (p.31, 159).
If you try to focus in One-Shot AF mode while the focus confirmation
light <o> in the viewfinder blinks, a picture cannot be taken. Press the
shutter button halfway again to focus, or focus manually (p.37, 67).
Slide the card’s write-protect switch to the Write/Erase setting (p.31).
Set the lens focus mode switch to <AF> (p.33).
To prevent camera shake, hold the camera still and press the shutter
button gently (p.36, 37).
If the lens has an Image Stabilizer, set the IS switch to <1>.
If a card error message is displayed, see page 40 or 209.
The camera turns off by itself.
Shooting-Related Problems
No images can be shot or recorded.
The image is out of focus.
The card cannot be used.