Moving Time Lapse Tutorial with $50 DIY Slider
Time lapses are my all-time favorite forms of video. Adding motion to your video makes the subject matter so much more interesting, and it adds a professional touch that cannot be achieved in video editing. Today I want to show you how to create moving time lapse videos using an iPhone 6 and $100 worth of photography equipment.
The process, or “What we did wrong and how we fixed it”.
I have an iPhone 6, which has time-lapse features already built-in. I just needed to figure out how I was going to get it to move slowly over a long period of time.
I found this camera tractor which costs about $50 on Amazon. Camera tractors are designed to be attached to a dolly (that old-school roller skate-looking thing).The idea is that you attach your phone to a dolly, and the tractor pulls it along at a steady rate to achieve fluid movement. The problem with this set-up is that it sucks.
Sure, you can get a moving time lapse, but due to the the nature of this set-up, you can never get a smooth video. The dolly wheels hit bumps and dips, and those tiny movements completely ruin the time lapse effect. Also, time lapse videos are best taken over a long period of time; this tractor doesn’t move slowly enough to get the subtlety I’m looking for.
To eliminate roughness, I got rid of the wheels; I took the wheels off the trolley to make it stationary and replaced the dolly with a rail. To compensate for the speed of the trolley, I added Lego gears to slow the thing down (details below)*.
What you’re going to need to add movement to a time lapse video**:
- Time lapse-enabled smart phone
- Camera tractor
- Slider/ Rail system
Take a look at how fast the gears are moving inside your device, and choose which gear to tie your string to. Attach your trolley to one end of your rail, and tie the loose end of the string to the slider. Then turn on the time lapse function on your iPhone, set it in the slider, turn on the tractor, and you’re ready to film.
*To get into what I did, let me first explain basic gear and wheel mechanics. Take a look at the diagram on the video. The gear that does the moving (the grey gear) is the driver gear; the gears that are moved by the driver gear are driven gears.
The smaller driver is moving the larger driven gear. Because the driven gear is five times as big, the driver gear must make five revolutions to complete one revolution on the driven gear, giving it a gear ratio of 5:1. In other words, if the driver gear turns at 10 revolutions per minute (RPM), the driven gear turns at a rate of 2 RPM.
In this diagram you see a series of smaller gears moving larger gears. What I did is I glued smaller gears on top of the larger gears, so that the stacked gears move together. Adding the small Lego gears slows down the gear train exponentially. For example, if the grey gear is moving at 25 RPM, then the green gear is moving at 5 RPM. Because the yellow gear is glued to the green gear, it is also moving at 5 RPM, which then moves the red gear at 1 RPM. According to the diagram in the video, the full gear train is moving at a ratio of 125:1
- Smart Phone: I use an iPhone 6, but any smart phone will do. If your camera doesn’t have a time lapse function, download an app like Hyperlapse.
- Trolley: Sevenoak SK-MS01 Motorized Push Cart.
- Slider/ Rail system: I use a Vanguard SBH 100 slider on a generic rail. A micro rail sells on Amazon for less than $30, but I’ve seen people make legitimate, smooth-running long rails from Ikea parts for the same price.