Canon EOS 70D Operation Manual - Page 171

F: 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. This is called bulb exposure. Use bulb exposures for night scenes, fireworks, astronomical objects, and other subjects requiring long exposures. 1 Set the Mode Dial to . 2 Set the desired aperture. While looking at the LCD panel, turn the or dial. 3 Take the picture. The exposure will continue for as long as you keep the shutter button Elapsed exposure time pressed completely. X The elapsed exposure time will be displayed on the LCD panel. Long exposures produce more noise than usual. If Auto ISO is set, the ISO speed will be ISO 400 (p.122). When [z4: Long exp. noise reduction] is set to [Auto] or [Enable], noise generated by the long exposure can be reduced (p.143). For bulb exposures, using a tripod and a remote switch (sold separately, p.184) is recommended. You can also use a remote controller (sold separately, p.184) 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. 171