T is for Time-lapse
The sun rises in 5 seconds, an orange decays before your eyes, and a storm comes rolling in, dumps rain and clears in mere moments. Are you tripping on that funny stuff from college again? Nope, just doing some time-lapse imaging for your next video production.
Time-lapse footage is always fun to use and work with in your video productions, and there are a large number of stock footage libraries out there, but these can sometimes be limiting. What happens if you need to capture your own time-lapse masterpiece? [an error occurred while processing this directive] There are several options. If you can afford it, traditional film cameras will allow you to under crank the frame rate to as little as one frame per second. With special additions and timers, frame rates can be even longer. This option is fairly expensive for everyday production.
Another option would be to use the time setting on many of the DV cameras on the market today. The Sony DSR PD150, for example, allows you to capture a second or two or video at predefined settings. Other video cameras have similar functions, but the disadvantage is that because these cameras can not capture a single frame, you will have to digitize your footage and then do a lot of math to calculate exactly how many frames were captured by the DV camera, how fast you want the final video clip, etc. This option also ties up your precious video camera and keeps you from going out and shooting other footage for your project.
With the advent of some very powerful and inexpensive digital still cameras, time-lapse video is easily within reach. With resolutions in the 4 mega pixel and higher range, using these images for video work has become very practical. I have a Canon PowerShot G2 (read the review here) that includes software for remote capturing. This software is excellent for doing stop motion animations, and even better for doing time-lapse effects. Cameras from Olympus, Sony, and JVC also include software to capture a series of pictures at regular intervals. I didn’t even know the free software that came with the camera could do this type of work, so if you haven’t checked your CD you might want to do that.
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| Check the software that came with your digital camera. Chances are you might have software to do time-lapse photography already. |
With a video camera, if you are trying to capture a process that is extremely long, you may not have enough battery or tape to capture the entire process. With a digital still camera, you can run off AC power and have the images saved directly to your hard drive.
Once you have your digital still camera and computer software set up and ready to go, you still need to do some math to figure out how often the camera should take a picture. Here is the math formula I used which may help you out.
1. Take the number of hours the process will take and multiply it by 60 to convert it to minutes. For example four hours will yield 240 minutes
2. Decide how long you want the time-lapse sequence to last (10 seconds for example) and convert it to frames (300 frames)
3. Divide minutes by frames to get the fraction of a minute (240/300= 0.8 seconds)
4. Use your middle school math and find the least common denominator (4/5ths of a second) and calculate the actual seconds (4*12=48 seconds) and you will have the correct interval for your frame rate.
So the formula is (Hours*60)/(seconds*30)=frame rate.
Here is a 5-hour time-lapse that I did this morning. To make it fit in the ten-second time; the frame rate was one frame per minute.
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| Click image to view QuickTime movie |
Next time we’ll use Adobe After Effects to remove strobing from time-lapse footage.
When not working deep in the labs of the DMN Central Division testing the latest and greatest software/hardware products Stephen Schleicher can be found at the local university teaching a few courses on video and web production. He can be reached at schleicher@mindspring.com. You can also visit him on the web at www.mindspring.com/~schleicher
Source: Digital Media Online, Inc.
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