Time-lapse Tutorial Part 3: Walk-through

1. Introduction and Planning
2. Equipment
3. Walkthrough
4. Post-processing, Presentation, and Distribution

OK, this part is fun, and really pretty easy. Let's shoot a cloudscape time-lapse. Collect your camera, fully charged batteries or other power supply, tripod, and either your computer or timer remote and appropriate cables. Head out to your favorite landscape or cityscape spot and take a look around. Decide how you would like to frame your shot. Remember that an HD video frame is wider than your camera's frame, so you will need to plan to cut off a bit from the top and/or bottom of your viewfinder. Look at the clouds. How fast are they moving, and in which direction? Do they cast any interesting shadows? Remember that they will move as well.

Once you have your framing decided, you will need to determine your exposure. Take a few test shots to see what looks right. You can do this in an auto mode to take advantage of your camera's meter. Just take note of the aperture, shutter speed, and ISO. If you are using an SLR, you can now dial in those settings in "M"anual mode, and connect either your timer remote or computer. Compact cameras need to be connected to a computer before the settings can be finalized.

With your camera set-up on a tripod and attached to your computer, open up your capture software. You should be able to access most compact camera controls through your computer. Check that your settings match those from your best test shot. Focus isn't too important for cloudscapes as long as everything in your frame is far away, your camera will always focus at or near infinity. Still, if focus lock is available, use it.

SLR users can focus normally. Just make sure you switch your lens to manual focus and disable any lens or in-body image stabilization. Also check your shooting mode. Single shot works best, as continuous shooting modes often result in duplicate frames, especially when using a remote.

Always be sure to use a preset or custom white balance! Auto white balance will shift from shot to shot causing a horrible flickering effect!

Now it's time to set your shooting interval. In most capture software, there is a shooting mode labeled as either "interval shooting" or "time-lapse". In this mode you can usually enter three settings. "Initial delay" tells the computer how long you want to wait before shooting, "Interval" is the amount of time your computer will wait between shots, and finally you can set the number of shots your computer will capture before stopping.

Timer remotes should have the same settings available. You will need to check your manual to determine how to set it up.

Generally, it is impossible to shoot faster than one frame per second. If the clouds are moving quickly, I would stick to the minimum one second interval, but for slower moving clouds, or for nearly still skies, you could try a two, three, four, or even five second interval. For a five second finished video, set the number of shots to 150, which gives you 30 frames for every second. More on timing later.

Once everything is set, you can start the capture sequence through either your computer or remote. Now sit back and don't touch anything. You can read, listen to music, whatever you like. Just keep listening to your camera. You can tell that everything is working by the sound alone. You can determine how long the sequence will take by multiplying the number of frames by the interval. 150 frames x 3 second interval = 450 seconds or 7.5 minutes. When the shoot is finished, why not try a slightly different variation, or adjust your timing a bit? When you're done for the day, it's time to head home to process those images into a movie.

Here's where a lot of people get stuck. Deciding on an interval for a time-lapse shot can seem like guess work, but if you approach it with a clear end result in mind, it becomes a fairly simple and logical process.

When I make a time-lapse clip, I usually intend to sell it. My distributors require that a clip last from 5 to 30 seconds. There's a starting point. I always produce full HD 1080p video at 30 frames per second (fps). 30 frames x 5 seconds = 150 frames. 30 frames x 30 seconds = 900 frames. So now I know that I need between 150 and 900 photos to make a 5 to 30 second clip. I also know that if I go over 900, that it's an easy task to remove unwanted frames (or speed up the final clip), but if I fall short of 150 it's very difficult to lengthen the clip.

Now for the guessing part. I need to decide how long it will take for the action in my scene to take place. For cloudscapes, I can look at the speed the clouds are moving and guess that it will take 10 minutes, or 30 minutes, or whatever, to see an interesting change in the clouds. When filming a flower opening, I can do a little research on the species to determine how long it will take. Again I want to err on the side of taking too many photos, that means a shorter interval.

For example, I know that a particular lily flower will open in about 12 hours. If I want the flower to appear to open in five seconds then:

12 hours = 720 minutes = 43200 seconds

43200 seconds / 150 frames = 288 seconds interval (4.8 minutes)

If I want to make that a 30 second clip:

43200 seconds / 900 frames = 48 seconds interval

In the above example I would probably set a 60 second interval, and let the shoot run a bit longer than I expect the flower to take to open. After all, nothing ever goes exactly as planned.

"Flicker" refers to subtle differences in exposure from frame to frame. The result is a sort of light strobe effect, or flickering, in either the shadow or highlight regions of your video. Many find this distracting.

Flicker can be caused by several factors. The worst offender is auto white balance. Again, always use either a preset or custom white balance setting. Next, still cameras are designed to expose within certain tolerances for a single frame. Shutter speed and aperture can very ever so slightly from shot to shot. You wouldn't notice the difference unless you rapidly view multiple frames one after another, as in a time-lapse sequence. Additionally, some light sources, such as standard fluorescent lights, cycle rapidly creating shot to shot variation.

There is usually very little you can do to control shutter speed variation. When working indoors under relatively low light, using a longer shutter speed, such as 1/4sec or longer, may help.

Aperture variance can be controlled to some degree by using either the largest or smallest aperture offered by your lens. F/2.8 or F/32 for example. Alternatively, if you have access to an older all manual SLR lens with an adapter for your camera, you can set the aperture with the aperture ring on the lens. This will guarantee zero variation from shot to shot. Many times you can ignore the aperture variance, but be aware that it may cause some flicker.


Finally, when working under artificial light, choose stable light sources. I find standard household incandescent bulbs to be the most reliable. Unfortunately, they run hot and use a lot of electricity. Lately, I've been using spiral type compact fluorescent bulbs successfully. Just be sure to let them warm up for about 20 minutes before you start shooting. I also recommend setting a custom white balance with a gray card, as the white balance presets rarely work with CFLs.

If you still find too much flicker appearing in your final shot, there are software solutions available. GBDeflicker by Granite Bay Software is one option. This is a last resort, however. Try to adjust your shooting style first.





On to part four ...