Nature will reveal fascinating things to those who are patient enough to stand and watch over a long period of time. Unfortunately, most of us can neither hold still that long, nor recognize a noteworthy change as it slowly manifests itself. Time-lapse photography solves these problems and creates an intriguing record of slow change over time.
Back in the days of 8-mm home movies, many movie cameras came with settings that allowed time-lapse shooting. As celluloid gave way to digital, I waited in vain for this feature to migrate to camcorders and then forgot about it.
A feature of modern life is that our gadgets can do far more than we probably realize. After owning my trusty Olympus SP-350 digital camera for nearly three years, I decided it was high time I found out more about the camera's capabilities. So I sat down with the manual and started reading. Imagine my delight when I discovered a section on time-lapse photography.
Setting The Camera
Like many digital cameras, my Olympus can also shoot movies, limited by the storage capacity in the memory card. But the time-lapse feature does not interact with the movie feature. It will shoot a series of up to 99 still images, in intervals ranging at one to 99 minutes in one-minute increments. Once you set up the time-lapse, pressing the shutter shoots the first photo. Then the camera goes into sleep mode until it's time to shoot the next one. I had worried that it might not be able to do an hour and 39 minutes of this on battery power alone; I don't have the AC adapter for this model. But in practice it wasn't a problem.
My day job office is on the fifth floor of a downtown San Jose office building with a nice view of the coast hills to the west. Clouds are often blowing in off the ocean, and sometimes the hills are veiled in patches of fog. I thought the view from my window would make an interesting subject, so I propped the camera in the windowsill and let it shoot the full 99 frames at one minute intervals. Before setting the camera for time-lapse, I also reduced the resolution of the shots to 640 x 480 pixels, to keep the resulting movie to a manageable size.
From Images to Movies
The result of the first attempt was 99 still images. There remained the problem of stringing them together into a movie. Fortunately, my Mac iBook came bundled with iMovie, a tool for making your own movies from a camcorder or other source of mpeg and mov format files that play in Quicktime and most other movie players. iMovie has a feature that lets you insert still photos into a movie, with setting to regulate how long the image is on the screen. The default is five seconds, and it also defaults to the very slow zoom into the image, which is apparently known as the “Ken Burns Effect”.
The instructions that follow for turning frames into movies will follow iMovie. Those of you who use a PC can easily find the equivalent software to do this.
First, open a new project. Before you go further, you should change some preference settings that will make your life easier when doing time-lapse movies.
Next, import your images. When you import files to iMovie, they import to the “storyboard,” which is a graphic set of flat frames containing a film clip or still in each one. You then drag each piece to a timeline near the bottom of the screen into the sequence you want. If you import 99 frames to the storyboard, moving them to the timeline is a bit finicky, and you can change the preferences so that files import directly to the timeline. When you import multiple files, they arrange on the storyboard or the timeline alphabetically. This is great for time-lapse projects, because the file names of the images created by the camera are in both alphabetical and chronological order. Just import all the files into iMovie, and all the images fall into place on the timeline.
Next select the entire timeline, and click on the icon for handling still images. Unclick the “Ken Burns Effect” checkbox, and then set the time on screen. This will apply to all the images on the timeline. In iMovie, the time index reflects, minutes, seconds, and frame number. So 05:11 in the time index for a single image means it will last for 5 seconds, plus the length of time used by eleven frames (depending on how many frames per second you have selected. I set the duration for 0:04. Given that the standard frame rate is about 18 frames per second, this works out to about .22 seconds per frame, or nearly 22 seconds for 99 frames.
After you set the time duration for each frame, sit back and let iMovies crunch the data as it sets all of the images for that duration. From within iMovie you can then play your movie and enjoy the wonders of time-lapse photography.
Finally, when you are satisfied with the results, select “Share…” from the File menu and export your movie in the format best suited for your needs, e.g., full quality, a CD-ROM, web streaming, etc. Here was the result of my first effort:
Movie 1. This is a time lapse movie of the sky in San Jose, California, looking west the day before the big storm of 04 January 2008. It was taken from my office window on the 5th floor of a downtown building.
Hints and Tips
Remember that if you are shooting an outdoor subject through a window you need to be careful of reflections. The second time-lapse movie I took ran into a few of these problems, because I was shooting closer to sunset, when the lighting situation changes radically.
Movie 2. More storm clouds looking west between 9:24 AM and 4:16 PM Pacific time on 08 January 2008.
In this case I took two sets of 99 frames one right after the other, but neglected to allow for the reflection of a homemade acrylic SOMA puzzle cube on the window sill. The camera was pointed through the glass at an oblique angle, and the reflection of the puzzle cube is clearly visible on the lower right part of the screen. Also, near the very end of the movie, you can see the reflection of other items in the room as it gets dark outside, and I unthinkingly decided to turn the lights on in the office.
But Is It Useful?
Knowing how to create time-lapse movies is one thing, but it raises another question: Suppose I took one of these from my window every afternoon. Looks cool, but is it scientifically useful data?
Apparently this is an open question. While corresponding with Forrest Mims about this article, he informed me that he is unaware of any set protocol for these kinds of movies as scientific data. I would appreciate hearing from any readers who are interested in discussing the development of such a protocol. But in the meantime, dive into your digital camera's user manual and see if you can create time-lapse movies. If you are shopping for a new digital camera, you may want to find out if a model you are thinking of buying can do this.
