How to do a time-lapse video with an iPhone

NOTE: This was originally posted on shutterstation.com, but since decommissioning that site I've pulled some of the articles here so they don't get lost. 

Time-lapse photography is a technique in which a camera is programed to capture one frame at a time with a relatively large interval between shots. These photographs are then put together into a movie that, when played at normal speed, gives the impression of time passing much faster than normal.

Doing a time-lapse requires a camera that can be programed to take, say a photo every 2 minutes, for a long period of time. Some point and shoots have this capability and you can buy accessories for a dSLR that will allow you to do it. But since I discovered a very cool app for the iPhone that automates the process I've been playing with it quite a bit. The app is conveniently called TimeLapse and it sells for.

In the app you can set up the interval between shots, the number of photographs, and the size. Then you just need to leave it to it and all the images will be stored in the iPhone photo library. The video below was done as a quick test from 170 images. I'll explain the process below.

You can just point the camera at something and pick a random interval and number of shots and get an interesting result, but you'll get much better results if you plan ahead. Here's what you need to define:

1. The time the event you want to capture will take

This is the amount of time the event takes in real life, that is, from when you start shooting to when you snap the last shot. For example, if you want to capture a sunset from full daylight to total darkness, the event might take around 2 hours (depending on where you live). But if you want to capture a flower blooming the event could take a couple of weeks. Whatever it is, convert it into seconds. Let's take the sunset example and assume we want to capture a 2 hour event. That's 7,200 seconds.

2. The length of the final video

How long do you want your video to last? Let's say we want the sunset to be shown in a 30 second video.

3. The frame rate you want to use

Frame rate refers to the frames per second (fps) at which our final video will play. The standard for film is 24 fps and that's what I like to use, but you can use whatever works best for you. 30fps (or 29.97 to be exact) is standard for television and the frame rate many video cameras use.

OK, so now we have the 3 variables that we need to calculate the Time Between Frames (TBF), which is the amount of time between one shot and the next. This is key for a time lapse video. The variables in the example are:

• Total time of event (TTE) in seconds = 7,200
• Total time of video (TTV) in seconds = 30
• Frame rate (fps) in frames per second = 24

The formula is:

• TBF = TTE / (TTV * fps) or TBF = 7,200 / (30*24)
• TBF = 10 seconds.

Now all we need to do is set TimeLapse (the app) to record an image every 10 seconds and to stop after 720 photographs (or 2 hours from the time you start). Set the iPhone somewhere safe where it won't move, and start the process. A few tips for shooting on the iPhone:

1. Ensure you have a full battery or the iPhone is plugged in.
2. Put the iPhone in Airplane Mode, as calls will interrupt the process.
3. Ensure you have enough space for all the photographs.
4. If you're going to capture more than 1000 images you'll have to rename, as the iPhone will go to 1000_1, 1000_2, etc. after 1000.

Once you're back at your computer, download all the images and drop them into a folder. Rename if you shot more than 1000 (you can use Automator on a Mac). To create the movie, I use Apple's QuickTime Pro, it's the easiest way and the software is cheap at $30. You can also use iMovie and Windows Movie Maker on a PC.

In QuickTime, all you need to do is go to the File menu and select 'Open Image Sequence', in the dialog box that appears select only the first photograph of the sequence and click Open. In the next dialog box select your frame rate and click OK. QuickTime will assemble the image and give you a preview. You can then save as a movie file and you're done.

You can buy TimeLapse directly from the App Store here.

To learn more about time lapse photography go here.