Friday, April 18, 2008

Using QuickTime to create stop-motion movies

While exploring the "Open Image Sequence" feature on Quicktime to create a simple Slideshow of images, I noticed that the combo box presented some values that were odd for someone trying to create a slideshow of pictures:

Although values like "3 seconds per frame" may seem acceptable for showing a slideshow of photos (each photo would be displayed for 3 seconds), "15 frames per second" seems to be just a little bit too fast to see all your photos (it means that 15 photos would be displayed in a second, which basically means that you wouldn't be appreciating any of them).

This got me thinking: "Why would you need to go through a slideshow in such a rush?". And then the geeky part of the brain kicked in and I remembered that this is how stop-motion animation movies work.

The idea of stop-motion is as old as cinema since the whole concept of films/movies is based on a stop-motion technique. Basically a camera is a mechanism that captures photos at a very fast rate (usually 24 frames per second). When we reproduce the captured images at the same rate, our brain fills in the gaps between the images, producing the illusion of movement.

Stop-motion works in that exact way: we capture some still images and then while reproducing them at a very fast rate, the images will perceive as having movement between them. To get a clear idea of how this is made, check out the Wikipedia page on this subject.

Excited with the idea of creating a stop-motion animation movie (basically because the movie "Nightmare Before Christmas" is one of my favourite movies of all time - well, at least my favourite animated musical) after discovering how easy it would be to put it all together on Quicktime, I decided to give it a try.

So, I mounted my camera (Canon Digital IXUS 400) on a tripod and took some sequenced photos of my USB Pen being disconnected from the USB hub. After putting it together on Quicktime, this is the result (reproduced at different speeds):
  • 6 frames per second:

  • 10 frames per second:

  • 15 frames per second:

Looks nice, eh? You can also apply this same concept to time lapse movies (that will be my next try).

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