Intervalometer

An intervalometer is a timer that triggers a camera's shutter automatically at set intervals. It comes as an external remote plugged into the camera or as a menu function built into the body. The photographer sets the gap between frames and the number of shots, and the camera then shoots on its own. It is the standard tool for time-lapses, star trails, and long unattended sessions.

Many current mirrorless cameras and DSLRs include an interval shooting function in the menu, and smartphones offer the same idea through time-lapse modes. Older bodies and some entry-level models leave it out, so external plug-in intervalometers remain popular. They cost little and add features such as bulb-mode timing and unlimited frame counts.

A self-timer delays a single shot, usually by 2 or 10 seconds, and then stops. An intervalometer keeps firing frame after frame at a set gap until it reaches the chosen count. A self-timer is enough for one group photo. A time-lapse, a star-trail stack, or a self-portrait session with many poses needs an intervalometer.

The camera sits locked on a tripod and takes one frame at a fixed gap, such as every two to ten seconds. Over an hour this produces hundreds of frames, and software assembles them into a short video. The interval sets the speed of the final clip: short gaps suit fast subjects like clouds, long gaps suit slow ones like plant growth.

Star-trail images are usually stacked from many exposures instead of taken as one. The intervalometer fires 30-second frames back to back for an hour or more, and stacking software blends them so the stars draw unbroken arcs. Shorter frames keep noise lower than a single extreme exposure, and a frame ruined by a passing car light can be dropped without losing the image.

Yes, and this is a main reason to buy an external unit. Most cameras stop at a 30-second shutter speed. In bulb mode the shutter stays open as long as the release is held, and an external intervalometer can hold it open for an exact programmed time, such as four minutes. This gives precise exposures far beyond the camera's built-in limit.

Yes, in two ways. Phone camera apps include time-lapse modes that shoot at intervals automatically. Most camera makers also offer remote-control apps that connect over Bluetooth or Wi-Fi and include interval shooting, which turns the phone into a wireless intervalometer. A dedicated plug-in remote still wins for long sessions because it does not drain the phone's battery.

Firing the camera without touching it removes the small shake caused by pressing the shutter button, the same benefit a remote release or a 2-second self-timer gives. On a solid tripod every frame comes out sharp and identical in framing. This matters most with long lenses and slow shutter speeds, where even a light touch can blur the frame.

Video plays at 24 to 30 frames per second, so each second of the final clip needs about 25 photos. A 10-second clip takes roughly 250 frames, and at a five-second interval those frames take about 20 minutes to capture. Planning backward from the clip length keeps sessions realistic and stops a memory card from filling with unused frames.

Manual focus and manual exposure keep every frame consistent. When autofocus hunts or auto exposure reacts to changing light, sharpness and brightness jump between frames and the finished time-lapse flickers. Setting focus, aperture, shutter speed, and ISO once before starting the timer produces a smooth sequence. A full battery and an empty memory card complete the checklist.