Lesson 35: Do the Time Warp

In Lesson 32, we downloaded Fast Camera and discussed using Fast Camera to take pictures of moving subjects. We also exported a series of photos as a movie. What we didn’t do was talk about time-lapse photography. That is what we are doing when we take a series of still images and then string them together into a video. When the video plays so that the photos are shown closer together in time than they were taken, that’s a time lapse.

This used to be (and still can be) something complicated and difficult to do, but Fast Camera makes it very easy. There are two tricks to creating interesting time-lapse videos. First, the camera must be still through the entire process of taking the photos. This is what happens when you follow a moving subject around and then try to create a time-lapse video from them:

It looks more like a series of photos of my dog than a time-lapse. While, technically, it is still a time-lapse video, because the background keeps changing, we lose sight of the fact that we’re watching a scene unfold. Instead of following a subject around, place the iPhone on the tripod we used back in Lesson 25 and again in Lesson 34. Or, refer to Lesson 34 for other ways to stabilize the phone. For this exercise, I used the tripod:


Notice the headset plugged into the iPhone. I used the volume up button on the headset to start and stop taking photos so I wouldn’t knock my precariously balanced iPhone over.

Putting the iPhone on a tripod for time-lapse photography also implies that there needs to be something moving in the frame while you take a series of photos. For example, you’ve probably seen some really awesome time-lapse videos of a flower blooming or of city traffic. In the first case, the subject remains in the frame the entire time but moves. In the second case, the subject is the city itself and the traffic driving through it provides the motion.

Another great subject for movement is water. When I chose the river as my subject, I was hoping for a nice big barge to go by or perhaps a low-flying Great Blue Heron. I didn’t get that lucky. The only boats that went by were so small and far away that they’re very hard to see. However, the movement of the water still creates interesting motion. As a side note, the small tripod on an uneven rock wall makes it rather difficult to get a level photo.

Here is a time lapse taken under a bridge:

And another looking down the river:

Could you spot the boats moving through the video? These were both shot with a 5 second delay between photos.

Another great subject for time lapse is any astronomical body. For the iPhone, the sunset is a safe bet. A couple of problems happened during my sunset time lapse. First, I used a 10-second delay between photos. Because of the lack of cloud motion, that was too fast. Second, the sun popped through the cloud coverage in a couple of frames, causing sudden overexposure. Finally, failing to take my own advice on making sure I had a fully charged phone before heading out to shoot, I ran out of juice before the sun had gone down. See Lesson 28 for tips on conserving battery life when you’re out to get a time-lapse–it is battery intensive. This is what it looks like:

The final thing to think about is what frame rate you want to create the video at. The frame rate is how many of the photos will be displayed per second. 30 frames per second is the rate that most movies are played at, so if you want a really smooth looking video, that would be the rate to choose. Since I took a smaller number of photos, I slowed things down a bit and exported my videos at 24 frames per second. Think of it this way: if you want 1 minute of video at 30 frames per second, you need 60*30=1800 photos.

Your Assignment: Open Fast Camera (and stop the photos if you have it set to start taking photos at launch) and follow the instructions below to set the time between photos. The faster the movement, the less time you need between photos to create a sense of movement. I used a 5 second delay for the river and a 10 second delay for the sunset. I would suggest using a 1 minute delay for the sunset instead, but it depends on whether the clouds are moving rapidly or not.

Now decide on your scene. If you don’t have one, you could try setting the phone up in your living room during a time when people (and/or pets) will be coming in and out. Time-lapse videos of families moving in and out of a room can be quite amusing.

Save and export your movie using the instructions in Lesson 32. Choose the frames per second based on whether you want it to look like a real video or whether you’d rather slow things down. You can also export the video and then go back and export it again at a different speed so you can decide what works best later.

What do you think? Is this a medium you could get into?