An Intervalometer is an external peripheral or integrated function to trigger exposures. The features commonly seen in intervalometers are:
- set or unlimited amount of exposures
- set time between exposures
- set time to start the exposure(s)
- length of exposures (for bulb photography)
Intervalometers exist as external devices, as integrated parts of the camera firmware, or as a software performing the function when the camera is connected to a computer via as USB cable. There are also special third party firmwares which have integrated intervalometers which can be used with some cameras which do not come equipped with such a function originally.