Canon EOS rebel xs - Manual (Page 101)

101
ShootingN
Each time you press the <B> button, the information display will
change.
About the Information Display
Focusing frame
Histogram
(Brightness/RGB)
ISO speed
Shots remaining
Exposure level Aperture
Shutter speed
AE lock
Picture Style
Battery check
Flash-ready
Flash exposure compensation
Drive mode
White balance
Live View exposure
simulation
Image-recording quality
When < > is displayed in white, it indicates that the Live View image
brightness is close to what the captured image will look like.
If < > is blinking, it indicates that the Live View image is not being
displayed at the suitable brightness due to low or bright light conditions.
However, the captured image will reflect the exposure setting.
If flash is used or bulb is set, the < > icon and histogram will be
grayed out. The histogram might not be properly displayed in low light or
bright light conditions.