Canon EOS-1 DX Mark III Advanced User's Manual page 244

Note
The field of view is approx. 100% (with image size set to JPEG/ ).
The camera will turn off automatically if left idle for the time set in [ : Auto power
off] ( ). When the setting is set to [Disable], the camera exits Live View shooting
automatically in approx. 30 min. and remains on.
With HDMI Cable HTC-100, you can display Live View images on a television ( ).
Note that no sound will be output.
You can view a histogram when [ : Expo. simulation] is set to [Enable] ( ) by
pressing the < > button repeatedly.
White display of the [ ] icon indicates that brightness of Live View images will
closely match the brightness of your shots.
If the [ ] icon is blinking, it indicates that the image is displayed at a brightness
that differs from the actual shooting result because of low- or bright-light conditions.
However, the actual image recorded will reflect the exposure setting. Note that the
noise may be more noticeable than the actual image recorded.
Exposure simulation may not be performed under some shooting settings. The
[ ] icon and histogram will be displayed in gray. The image will be displayed on
the screen at the standard brightness. The histogram may not be properly
displayed in low- or bright-light conditions.
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