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Trigger Time: Intervalometer Basics for Time-Lapse and Long Exposures

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Read Time: 7 min
This post is part of a series called Time-Lapse and Long Exposure.
Creating a Starlight Time Lapse Video
Sunrise, Noon, Sunset: How to Plan Your Outdoor Photoshoot With SunCalc

Many years ago, I first played with a Canon Powershot G3. I knew little about photography but I understood animation and image sequences. Most of the functions on the little camera were utter gibberish to me except one feature that had me in awe: the Intervalometer. 

An intervalometer, or remote timer, is basically a way to take a sequence of many photographs automatically. You sometimes find this feature in your camera menu or you can use an external device.

With the intervalometer feature I could effortlessy produce live stop-motion or time-lapse sequences by programming the G3 to take photos automatically. I would then stitch my sequences together and viola: video. Watching the world whizz by in variable speeds was magical, but the quality wasn't great.

A busy airport arrivals loungeA busy airport arrivals loungeA busy airport arrivals lounge

Fast forward some years and I now own a couple of DSLR’s, the functions are no longer gibberish, instead they are my friends, giving my quality level a well-needed boost.

However, neither of my DSLR’s contained an intervalometer feature. Denied of my passion for time-lapse photography I grumbled a bit and finally invested in some external devices to fill the void.

As much as I think intervalometers should be a basic feature in any camera, even my iPhone can do this, I learned there are actually some advantages to having a remote trigger or ‘off camera’ intervalometer.

So why would you need one?

Intervalometer with SLR cameraIntervalometer with SLR cameraIntervalometer with SLR camera

Trigger Button

Almost all intervalometers will come with a large trigger button.

This is useful because even a stills camera on a tripod is prone to shake when you hit the button. Of course you can always set the camera’s delay timer to take a shot after 2 or 10 seconds but you might miss a perfect moment. Even more annoying is forgetting to set the camera back again and missing more perfect moments.

Using a trigger button on a intervalometer takes away the risk factor of shaking the camera and also gives you the opportunity to trigger the camera exactly when you want to without touching the camera.

The other benefit of taking your hands off of the camera is when taking portraits. Particularly with nervous subjects or children. After taking a moment to set up your shot you can step away from the camera and focus instead on getting your subject to relax or behave. With your finger firmly on the trigger its just a matter of waiting for that perfect moment to happen and then fire away.

Trigger with delayTrigger with delayTrigger with delay

Trigger Delay 

Other than manually triggering the camera you can also set a delay to decide when the camera begins shooting.

Your camera will usually have a time delay of 2 or 10 seconds. With an intervalometer you can decide to trigger the camera pretty much whenever you want. Maybe you want the camera to trigger in a couple of hours or maybe a few days. The trigger delay setting is most useful for times of day where you might be either too busy or possibly sleeping.

Maybe you’re on holiday and you know you are going to get an epic sunset from your hotel balcony but it’s also your last night and you should probably be taking your significant other out to a classy restaurant. Assuming you took a tripod and an intervalometer with you on your holiday, no problem. Simply set up the shot and configure the timer to fire off some shots when the magic begins, cross fingers and review later on. You can always use your smart phone to calculate sun positions and times.

Of course there is an increased element of chance when relying on the camera to begin automatically without your supervision. The most common use for a trigger delay is for setting off a time-lapse sequence. Whether its sunset, sunrise or simply not shaking the camera when a sequence begins. An intervalometer really comes into its own when used for time-lapse.

Trigger with IntervalTrigger with IntervalTrigger with Interval


Allowing the camera to take automatic sequences with a set time between photographs is really the killer feature of an intervalometer. The interval setting is where you determine how much time passes between each photograph is taken. This is essential for time-lapses.

Maybe you want to capture clouds whizzing past or watch crowds dashing around like crazy. In these circumstances you could set a relatively low interval such as 3 to 5 seconds.

Or maybe you want to capture movement that can’t be seen by the human eye such as shadows creeping over buildings. In those situations you would use an extended interval, maybe 15 to 30 seconds.

The only thing to keep your eye on is that your interval time does not exceed your exposure length. Your camera will still be controlling the shutter speed and your intervalometer doesn’t really care about this. Worst case scenario you end up with less images than you expect because the camera is still busy processing an image whilst trying to trigger the next image.

Intervalometer with bulbb or longIntervalometer with bulbb or longIntervalometer with bulbb or long

Bulb (or Long)

Maybe time-lapse isn’t really your thing and instead you’re more interested in light painting and star trails. Most cameras will come with a mode known as Bulb. Bulb mode is essentially exposing an image for a longer time than others modes such as Manual will allow. It’s pretty useless in the daytime but at night and in darker conditions it’s a great feature.

Long exposure of traffic using bulbLong exposure of traffic using bulbLong exposure of traffic using bulb
Long exposure creates the light trails from car lamps

In Bulb mode you essentially hold down the shutter button for a really long time and let go when you think your image is exposed. The concept is great but counter-intuitive. If you are shooting a super long exposure the last thing you should be doing is touching the camera.

When you control Bulb (often called Long just to add to the confusion) on an intervalometer you simply program how long the image should expose without touching the camera. Using a hands-free shutter speed reduces the shake and prevents you from holding down the button for a really long time freeing you up to paint light or enjoy a warm cocoa.


The last feature you will find on an intervalometer is the number feature. Often depicted by a large ominous N. The N stands for the number of pictures.

Assuming that you are going to shoot a timelapse sequence then you’ll probably need to take a few hundred photographs to turn your sequence into a video. The number function will allow you to do just that.

Depending on what brand of intervalometer you have the number limits will vary. My official Canon intervalometer goes up to 99 photographs. At 25 frames per second this gives me a measly four seconds of video.

What might not be instantly obvious is that setting the timer to 0 will actually take an infinite sequence. Infinite if your memory card never fills up or your camera battery never dies, that is.

Other intervalometers seem to be programmable up to about 399 frames which will give you a more generous 16 seconds of video.

At this point everything starts to get a little bit too mathematical, at least you can always turn to some smart apps and various time-lapse calculators to ease the headache.

A streamA streamA stream

Other Alternatives

Intervalometers range from ridiculously cheap to insanely expensive but should be in every photographers toolkit. Taking a dongle approach is super convenient but not the only way you can remotely control your camera.

If you’re not lucky enough to have an intervalometer built into your camera you can always look into installing firmware hacks like Magic Lantern. You can check the software that came with your camera and see if there’s a way to tether your camera to a laptop and trigger it via USB or wifi. If you’re super lucky you might find compatible apps for your smart phone that can communicate with your camera. The super geeky amongst you can explore using light and sound to trigger your camera.

Whatever your approach, taking your hands off the camera and experimenting with triggering your camera remotely opens up endless new ways to increase your creativity and improve your photography skills.

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