From a Digital Photo magazine article by Tom Bol, January 28, 2015
If you’ve recently gone to the movies, watched TV or surfed YouTube videos, chances are good you’ve seen some time-lapse photography. Time-lapse photography is all the rage right now. Feature films and documentaries have long used time-lapse photography to wow viewers. Remember watching the flower grow from seedling to mature plant in mere seconds, or watching the stars rotate in the night sky over a jagged Himalayan peak? Time-lapse photography was once a complex process reserved for high-end productions, but not anymore. Today this dazzling technique is available for any photographer, and it’s never been easier. Some DSLRs even create the movie in camera. Time to get out and shoot some time-lapse!
How it works. Time-lapse photography involves shooting a large number of frames over a long period of time, and then merging them into a movie. Two hours of shooting time and hundreds of frames can be merged into a 10 second movie clip, in essence speeding up time from hours to seconds. On the extreme end, some time-lapse photography involves shooting over the course of weeks and months, and then merging the sequence into a few brief minutes of footage.
The possibilities are very exciting. Imagine watching your next two-hour photo shoot from start to finish in a 20 or 30 second movie or seeing the transformation of light from a rosy sunset to a starry night in 30 seconds of video. See some interesting clouds passing overhead? Some of the best time-lapse sequences record passing storms and interesting clouds streaking through the sky. You can also combine several time-lapse sequences into a longer video.
To shoot time-lapse, we need an intervalometer. This device simply counts intervals. For photography, there are two popular options for intervalometers - either in-camera or an intervalometer cable release. Camera manufacturers took note of the popularity of time-lapse photography, and a number of cameras have intervalometers built right into the camera. All one need do is set up the sequence and hit the shutter button. Some cameras take this a step further, and offer a time-lapse movie option where the camera actually creates the final movie once the sequence is complete.
Shooting the sequence. Once you have the gear needed, its time to shoot your time-lapse sequence. Start simple; don’t go for the three-hour sunset to stars sequence over El Capitan on your first attempt. Better to try a midday shot of passing cumulus clouds over your house.
The first consideration is exposure mode. It might sound logical to use an automatic mode like aperture priority to adjust for any differences in exposure during the time-lapse. But this can cause a lot of headaches when you seam all the frames together after the shot. Flicker is a common problem in time-lapse movies, and is often caused by different exposures during the sequence. The better choice is manual mode.
Determine exposure using manual mode so it stays consistent for every shot. The ambient light in the scene might change during the sequence, but today’s cameras have great dynamic range and can handle slight exposure shifts. Next, focus on your subject and turn off autofocus. If your lens autofocuses for each shot, it might miss frames as the lens focuses back and forth. Shoot on a tripod to keep each frame identical in composition, critical when you make your final movie. Turn off any vibration reduction/image stabilization since the camera is stable on my tripod. Finally, set your white balance at a set value. Don’t use Auto and risk having the camera change white balance between exposures.
Once the camera is ready to go, it’s time to configure your intervalometer. This can be daunting at first. What is the right amount of time and delay between frames for your subject? Try this formula with simple daylight scenes like passing clouds or flowing water. Set your shooting delay for five seconds between frames and overall time for 25 minutes. You will capture 300 frames in 25 minutes, and a 24fps movie clip will be approximately 12 seconds long. For rotating stars at night, try using ISO 3200, a 20 second exposure at f4, and a delay between shots of five seconds. Focusing at night can be difficult. Try setting your camera to infinity focus, or using live view to help focus on stars. Make sure you have a fresh battery in your camera. If you have your Long Exposure Noise Reduction set to “on”, turn it off.
These shooting formulas are only the beginning. Experiment with your time between shots depending on the speed of your subject. Busy street scenes with people walking and cars driving past can be shot with a quick interval like 1-2 seconds. Slow moving subjects will require a longer interval between shots.
Here’s how to calculate an interval between shots: say you want to record two hours of time-lapse. There are 2 hours x 60 minutes per hour x 60 seconds per minute = 7200 seconds in two hours. Next, say you want to compress these two hours into a one-minute movie - that’s 60 seconds of movie. Dividing 7200 by 60 gives us an interval of 120 seconds or two minutes between exposures. After setting your exposure, set your interval to two minutes and off you go. Your camera will take one exposure every two minutes for two hours.
Another consideration is image quality. If you shoot RAW, you’ll need more compact flash capacity then if you’re shooting JPEG. RAW images will give you better options to adjust images after the sequence, but take a lot of processing power and more hard drive space.
Creating the time-lapse movie. Now you have the frames shot, it is time to make the movie. If you have an in-camera movie option, try that out first. Choose the movie quality settings before shooting the sequence, and the camera creates the movie after the all the frames are shot. Then simply download the movie off the flash card and it is ready to go.
Most time-lapse sequences are created in the computer with image editing software. There are many ways to create time-lapse movies including advanced workflows using Final Cut X and Adobe After Effects. But if you’re just starting out, one of the easiest methods is using QuickTime Pro 7.
This inexpensive software provides simple control of the movie creation. To start, you’ll need to convert your RAW files to JPEG or TIFF because QuickTime Pro 7 doesn’t work with RAW images. Next, put all your sequence images into one folder on your desktop. Open QuickTime Pro, and choose File-Open Image Sequence. Navigate to your folder of images, and select the first image in the sequence. Click Open, and choose the frame rate for your movie. We suggest 24fps for smooth video clips, but you can choose any frame rate you like. Once you click on the frame rate, QuickTime creates your time-lapse movie. You may have to minimize the window to see your movie (the movie often comes out as big as your screen or larger). Choose ‘View’ in the menu, and choose ‘fit to screen’. Once your time-lapse is created, you can edit and export the movie according to your desired end use.
Time-lapse photography is a quick and easy way to liven up your photography. The next time you are watching clouds race overhead, grab your camera and shoot a time-lapse sequence. You won’t believe how good accelerated time can look.