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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. ==Photography== In photography, intervalometers are used to trigger exposures. 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 Digital Single Lens Reflex (DSLR) cameras are limited to 30 second or shorter exposures. An intervalometer can be used to take long (>30 seconds) or very long exposures (minutes or hours) using the "Bulb" setting. Long and very long exposures taken at night can be combined to create timelapse animations, star trails, or using astrophotography processing techniques to create images of objects in the night sky like nebulae and galaxies. 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 cameras. Later, standalone 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 was 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 and Pentax DSLRs (Nikon D2H, D2X, D2Xs, D3, D3s, D4, D4s, D800, D800E, D810, D750, D700, D600, D610, D200, D300, D300s, D7000, D7100, D5000, D5100, D5200, D5300, Pentax K-5, K-r, K-30, K-50, K-5 II, K-5 IIs and K3), Panasonic GH3 as well as Nikon and Pentax mirrorless interchangeable-lens cameras (Nikon 1 J1, V1, J2, V2, Pentax Q, K-01, Q10, Q7) have built-in intervalometers. CHDK is a firmware add-on for many Canon PowerShot cameras that among other features can provide an intervalometer. The Magic Lantern add-on firmware adds many functions including an intervalometer to Canon 5D Mark II, 550D, 60D, 600D, 50D and 500D cameras. Pentax Optio W-series compact cameras (Optio W10,W20,W60,W90,WG-1) as well as Optio 555 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 10 seconds to 99 minutes. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「intervalometer」の詳細全文を読む スポンサード リンク
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