Canon eos rebel T2i - Manual (Page 84)

a : Manual Exposure
84
In step 2 on the preceding page, turn the
<6> dial to the left to set <BULB>. A
bulb exposure keeps the shutter open for
as long as you hold down the shutter
button. It can be used to photograph
fireworks, etc. The elapsed exposure
time will be displayed on the LCD
monitor.
Bulb Exposures
Since bulb exposures produce more noise than usual, the image might
look a little grainy.
You can reduce this noise by setting the [7 Custom Functions (C.Fn)]
menu’s [Long exp. noise reduction] to [1: Auto] or [2: On] (p.193).
For bulb exposures, using a tripod and Remote Switch (p.204, 205) is
recommended.
You can also use a remote controller (sold separately, p.204) for bulb
exposures. When you press the remote controller’s 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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