Intervalometer

From Wikipedia, the free encyclopedia

An intervalometer is a device which counts intervals of time. (Other names include interval meter and interval timer). Such devices commonly are used to signal, in accurate time intervals, the operation of some other device. For instance, an intervalometer might activate something every 30 seconds.

Contents 1 Photography 2 Military Application 3 Home 4 References

[edit] Photography

In photography, intervalometers are used to trigger exposures. This is often done for a time-lapse series. It may also be used to start taking picture(s) after a set delay. For example, in aerial photography, one may want to delay the start until five minutes after take-off, to allow time to reach altitude.

Most modern cameras include the most basic intervalometer functionality, the "self-timer". This delays the shutter release for a short time, allowing the photographer to get into the picture, for example.

In the past, intervalometers were external devices which interfaced to a camera to trigger taking a picture, or series of pictures, at a set time. These sometimes used existing remote shutter features on existing cameras. Later, products commonly referred to as intervalometers have added capabilities far beyond the basics of just measuring, and signaling, a time interval. One of the first features that was added to intervalometers is the ability to use an external event to signal the start of the time interval(s). The ability to sense an external event is such a common feature of intervalometer products that many people do not distinguish between the sensing of the event and the measuring of time intervals.

What is meant when someone refers to an "intervalometer" must be determined from context. Some possibilities are: time-lapse capability (strictly an intervalometer function), sensing of a remote event, a time delay longer than what most consider the "self-timer" range, etc. Strictly speaking, an intervalometer only measures, and/or signals, time intervals.

Almost all digital cameras have the basic hardware capability required for intervalometer functions: knowing the current and elapsed times. The implementation of more advanced functions is a matter of what the manufacturer chooses to implement in the camera's firmware. Functions beyond the self-timer are beginning to be seen in some digital cameras, and are used in some cases to distinguish models within a camera line.

Nikon D2 series (models D3, D200, D300, D700 and D5000) have built-in intervalometers, and if you have the oldest camera you can use the Multi-function Remote (MC-36) as an intervalometer.

The CHDK project has modified the firmware for many Canon PowerShot cameras to add scripting abilities, and hence programmable intervalometers (among others)^[1].

[edit] Military Application

The ALE-39 countermeasures system uses intervalometers manufactured by Ledex Inc. (now part of Johnson Electric) of Dayton, Ohio. The ALE-39 can fire flares in a synchronized pattern, very rapidly and with great reliability. The intervalometer used in the ALE-39 is essentially a solenoid-actuated rotary switch driven by solid-state timing circuits.

[edit] Home

One of the more common types of intervalometers is the timer that is used to turn lights on and off at set times. These are commonly used by people when they go on vacation. There are also a large number of commercial and industrial applications for even such basic intervalometers.

[edit] References