Canon EOS R5 Mark II Advanced User's Manual page 150

3.
Take the picture.
The exposure will continue for as long as you keep the shutter button
pressed completely.
Elapsed exposure time is displayed on the LCD panel.
Caution
Do not point the camera toward an intense light source, such as the sun or an
intense artificial light source. Doing so may damage the image sensor or the
camera's internal components.
Long bulb exposures produce more noise in the image than usual.
ISO 400 is used when the camera is set to ISO Auto.
When shooting bulb exposures with the self-timer instead of the bulb timer, keep
pressing the shutter button completely (for the self-timer time and bulb exposure
time).
Note
You can reduce the noise generated during long exposures by using [
exp. noise reduction] (
Using a tripod and the bulb timer is recommended for bulb exposures.
You can also shoot bulb exposures with Remote Switch RS-80N3 (sold
separately, ).
You can also shoot bulb exposures with Wireless Remote Control BR-E1 (sold
separately). When you press the remote controller's release (transmit) button, the
bulb exposure will start immediately or 2 sec. later. Press the button again to stop
the bulb exposure.
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