The ABC of Photography – B (Bulb)
The Bulb setting (abbreviated B) on camera shutters is a momentary-action mode that holds shutters open for as long as a photographer depresses the shutter-release button. The Bulb setting is distinct from the shutter’s Time(T) setting, which is an alternate-action mode where the shutter opens when the shutter-release button is pressed and released once and closes when the button is actuated again.
The bulb setting is used on some cameras, including some point-and-shoot cameras, to obtain shutter speeds slower than the minimum offered by the camera otherwise.
Because of the risk of camera movement, the camera is most often mounted on a tripod for the duration of the exposure. While it is generally possible to use the shutter release button on the camera itself, a cable release or electronic remote is often used to further eliminate the risk of shaking the camera during long exposures. The cable releases generally include a locking feature to eliminate the need to keep the button or plunger depressed during extremely long exposures.
The bulb setting is useful for the following types of photographic subjects:
- fireworks at night
- the night sky and celestial objects (see astrophotography)
- streets at night (creating streaks from moving cars)
- light painting
Sources: Pixabay, Wikipedia, Susan Wingfield Lamar High School