Intervalometer
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.
In photography
, intervalometers are used to trigger exposure
s. This is often done for a time-lapse
series. It may also be used to take, or begin taking, picture(s) after a set delay.
Examples of intervalometer use in aerial photography
include delaying the start of picture taking by an unattended camera until some time after takeoff and separating multiple exposures in time, and thus distance as the vehicle containing the camera travels, to obtain the 3D effect (stereoscopy
). To obtain the 3D effect each image should have about 60% of the surface in common with either the preceding or following image. The interval is calculated as a function of the altitude and speed of the vehicle; shorter intervals for low altitude and high speed.
Often the purpose of a photographic intervalometer is to reduce the resources required either to take the pictures or post-process them as similar images could be obtained by having the camera continuously take pictures as rapidly as possible. Using an intervalometer permits restricting the pictures taken to only those with the desired content. This reduces the requirements for resources such as power and storage media (e.g. film or memory card space).
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.
The Nikon D2 series (models D3, D200, D300, D700, D5000, and D7000) have built-in intervalometers. Older Nikon cameras can use the Multi-function Remote (MC-36) as an intervalometer.
The CHDK project has modified the firmware for many Canon PowerShot
cameras adding many additional capabilities. Among these additional features are both moderate intervalometer capability and the ability to run scripts. Several scripts have been developed that have fully featured intervalometer capabilities.
Pentax Optio W-series compact cameras (Optio W10,W20,W60,W90,WG-1) have a built-in basic intervalometer. The camera is put in standby mode between shots to reduce power. The intervalometer can be set to take up to 1000 pictures at a user settable interval of up to 99 minutes. If the batteries last, this results in a maximum total elapsed time of 68.75 days.
Photography
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
, intervalometers are used to trigger exposure
Exposure (photography)
In photography, exposure is the total amount of light allowed to fall on the photographic medium during the process of taking a photograph. Exposure is measured in lux seconds, and can be computed from exposure value and scene luminance over a specified area.In photographic jargon, an exposure...
s. This is often done for a time-lapse
Time-lapse
Time-lapse photography is a cinematography technique whereby the frequency at which film frames are captured is much lower than that which will be used to play the sequence back. When replayed at normal speed, time appears to be moving faster and thus lapsing...
series. It may also be used to take, or begin taking, picture(s) after a set delay.
Examples of intervalometer use in aerial photography
Aerial photography
Aerial photography is the taking of photographs of the ground from an elevated position. The term usually refers to images in which the camera is not supported by a ground-based structure. Cameras may be hand held or mounted, and photographs may be taken by a photographer, triggered remotely or...
include delaying the start of picture taking by an unattended camera until some time after takeoff and separating multiple exposures in time, and thus distance as the vehicle containing the camera travels, to obtain the 3D effect (stereoscopy
Stereoscopy
Stereoscopy refers to a technique for creating or enhancing the illusion of depth in an image by presenting two offset images separately to the left and right eye of the viewer. Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth...
). To obtain the 3D effect each image should have about 60% of the surface in common with either the preceding or following image. The interval is calculated as a function of the altitude and speed of the vehicle; shorter intervals for low altitude and high speed.
Often the purpose of a photographic intervalometer is to reduce the resources required either to take the pictures or post-process them as similar images could be obtained by having the camera continuously take pictures as rapidly as possible. Using an intervalometer permits restricting the pictures taken to only those with the desired content. This reduces the requirements for resources such as power and storage media (e.g. film or memory card space).
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
Shutter (photography)
In photography, a shutter is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or a light-sensitive electronic sensor to light to capture a permanent image of a scene...
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.
The Nikon D2 series (models D3, D200, D300, D700, D5000, and D7000) have built-in intervalometers. Older Nikon cameras can use the Multi-function Remote (MC-36) as an intervalometer.
The CHDK project has modified the firmware for many Canon PowerShot
Canon PowerShot
The PowerShot products are a line of consumer and prosumer grade digital cameras, launched by Canon in 1996. The PowerShot line has been successful for Canon, and is one of the best-selling digital camera lines worldwide....
cameras adding many additional capabilities. Among these additional features are both moderate intervalometer capability and the ability to run scripts. Several scripts have been developed that have fully featured intervalometer capabilities.
Pentax Optio W-series compact cameras (Optio W10,W20,W60,W90,WG-1) have a built-in basic intervalometer. The camera is put in standby mode between shots to reduce power. The intervalometer can be set to take up to 1000 pictures at a user settable interval of up to 99 minutes. If the batteries last, this results in a maximum total elapsed time of 68.75 days.