So after the Relay for Life time lapse I did, I decided I needed to learn more about this time lapse stuff. Turns out it is really really awesome. Okay, I knew that already. But turns out there is a lot that I didn’t know about time lapse photography. Most of my assumptions about how far apart shots should be and what frame rate to show them at was completely wrong.
So bear with me as I explain what I’ve learned. Keep in mind I’ve never done video and I’m a total n00b when it comes to this stuff.
Wrong Assumptions
My first assumption was that if the pictures in a time lapse sequence are closer together, it makes the video appear to be more smooth. Wrong! What makes a time lapse look smooth is all about frames per second. To make sense of that, you just have to realize that TV and movies are typically somewhere around 24 – 30 frames per second. If you live in the UK, TV is broadcast at 24 frames per second. In the US, it is 30 frames per second. That means you are basically seeing 30 still images per second. When put together, they appear to be in motion. Anything less than 24 frames per second looks visibly choppy. So a smooth looking time lapse has little to do with how far the images are spaced apart. If the images are closer together, say 1 second, and displayed at 24+ frames per second, the time lapse will move more slowly. If the images are say 20 seconds apart, and displayed at 24+ frames per second, the time lapse will move very quickly.
Second assumption I made was that a faster shutter speed will make the time lapse look better. Wrong! This goes back to the frame rate again. Turns out that 30 blurry frames displayed in 1 second actually doesn’t look blurry at all. Try this out on your DVR. Just pause the TV and look at the paused image. It will look blurry, but when it is flashing past your eyes at 30 frames per second, it is not blurry. So shutter speeds of 1 second or even more are perfectly acceptable in time lapse photography.
Using the right tools
iMovie is not the right tool to use for time lapse photography. It just wasn’t designed to do it. I assume because Apple already has a couple of tools that were designed to do time lapse correctly. The fastest frames per second iMovie will let you string together a series of stills is 10 frames per second. 24 – 30 is the goal, but even 15 frames per second is much more smooth than 10.
The right tool for the job is either Final Cut Pro, Adobe Premier Pro, or Quicktime Pro. The latter of which is only $30 compared to $999 and $799 respectively. Quicktime Pro will suit my needs just fine thank you very much. Actually Quicktime Pro is pretty nice. You choose from the file menu to open an image sequence. Then it asks you what frame rate you want, i.e. 15, 24, 30, etc. That’s it. Very simple. It has other editing capabilities too, but I found it easiest to take the .mov file created by Quicktime, import it into iMovie and add text, transitions, music, etc.
Second Attempt
With my newfound knowledge, I took advantage of the awesome clouds we’ve been getting and did a time lapse sequence out at Parowan Gap at sunset. The thing about time lapse photography is that it is a slow learning process. It takes a lot of time and effort to get a few seconds worth of video. I didn’t entirely think things through with this one. I just kind of shot-in-the-dark and set up the interval timer to take a shot every 20 seconds. I let it shoot until the sun went down. In retrospect, I wish I had gone with a shot every 7 or 5 seconds so that the video wasn’t so short. I ended up shooting for one and a half hours. That resulted in a 10 second video at 24 frames per second. I went with 15 frames per second and got 16 seconds out of it and it still looks pretty smooth, but not as smooth as I would like it.
Frame Rate and Resolution
If you’ve been thinking this through, you have probably realized that in addition to time, time lapse photography will take a lot of space on your memory cards. Ideally, you would want to shoot in RAW. Let’s assume you want a 30 second video at 30 frames per second. That means you need to shoot 30 x 30 = 900 frames. On my 12 MP camera, I can fit about 270 RAW images on a 4GB card. So you would need over 13 GB of storage space to get 30 seconds worth of footage!
The thing you need to keep in mind is resolution. A RAW or even full size JPG on my camera is 4288 x 2848 pixels big. Now realize that the largest an image needs to be for HD video is 1920 x 1080 pixels for 1080p. At 720p, the images need to be 1280 x 720 pixels. Online video sharing sites do HD at 1280 x 720, at least Vimeo does. So 4288 pixels is way overkill even for HD video. If you have the GB to spare or are shooting for a big movie screen, then by all means shoot in RAW. Just something to consider. Note, my camera makes larger images in the very lowest JPG mode than are even needed for 1080p HD video. So you may want to compromise. Somewhere between RAW and the lowest JPG setting will likely be sufficient for your needs. Chances are most people will never see your video in HD if you are just sharing it on the web.
Summary
So here is my basic list for doing time lapse photography:
- Shoot on a tripod (should be a given)
- Shoot in manual focus
- Shoot in manual mode (set shutter, aperture, etc. manually)
- Calculate how many shots you need based on frame rate (24 – 30 fps) and the length you want your video
- Turn VR off
I can’t wait to try more.