Canon EOS M Basic Instruction Manual page 229

When shooting, note the following:
Image on the LCD monitor
Under low- or bright-light condi ions, the Live View image may not reflect
the brightness of the captured image.
If the light source within he image changes, the screen may flicker. If this
happens, stop shooting and resume shooting under the actual light
source.
If you point the camera in a different direction, the image brightness may
change greatly momentarily. Wait until the brightness level stabilizes
before shooting.
If there is a very bright light source in the picture, the bright area may
appear black on the LCD monitor. In still photos, such bright areas will be
recorded properly as a bright area. In movies, the bright areas will be
recorded in almost the same way you see it on the LCD monitor.
In low-light conditions, if you set [52: LCD brightness] to a brighter
setting, the image on the LCD monitor may develop chrominance noise.
However, this chrominance noise will not be recorded in the image.
When you magnify the image, the image sharpness may look more
pronounced than in the actual image.
Lens and Flash
The focus preset feature of some lenses cannot be used with this
camera.
Firing a modeling flash is not possible with the camera.
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