Canon EOS R50 Mirrorless Camera (White) - Manual (Page 144)

Long (Bulb) Exposures
In this mode, the shutter stays open as long as you hold down the shutter button completely,
and closes when you let go of the shutter button. Use bulb exposures for night scenes,
fireworks, astrophotography, and other subjects requiring long exposures.
1.
Set the Mode dial to <M>.
2.
Set the shutter speed to [BULB].
Turn the < > dial to the left to set [ BULB ].
3.
Set the desired aperture value.
Press the < > key to select the aperture value, then turn the < >
dial to set a value.
4.
Take the picture.
The exposure will continue for as long as you keep the shutter button
pressed completely.
Elapsed exposure time is shown on the screen.
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