Self-timer
A self-timer is a mechanism which is used to trigger the shutter after a set period of time - allowing the photographer to be in the picture, or to avoid vibrations introduced by fingers. This mechanism is either built into the shutter release of a camera or used as an add-on accessory.
Older mechanical self-timers, such as those on old Leicas or sold as accessory, typically employed some sort of a resistance coil. The user would pre-wind the coil to load it with tension, and then it would unwind. When it finished unwinding it would trip the shutter release. Accessory self-timers can be used by screwing into the shutter release button; and most have the ability to adjust the trip mechanism length to match the specific camera. A special type are self timers that can be used for the cable release instead of the shutter release button.
Modern electronic cameras use digital timers. Most digital timers have a set time (eg, 10 seconds) which counts down, giving beeps or flashing LEDs as warnings, and then trips the shutter. Some electronic cameras offer the ability to select a desired length of time.
accessory self-timer by scenery_and_fish (Image rights) |
pneumatic accessory self-timer by Siim Vahur (Image rights) |
electronic self-timer by David Johnson (Image rights) |
Instructions for use Yashica Mechanical Self Timer image by Pablo Coronel (Image rights) |