Time-Lapse

Time-Lapse Photography
by Dennis Allen

July 30, 2011

August 28, 2011

If you want to duplicate my first attempts at time-lapse, you need to set your camera up in manual mode, focused to infinity, ISO1600. Somewhere in your camera’s menus is a mode equivalent of dark frame subtraction. In other words, on a 30 second exposure the camera will take a 30 second dark frame. This dark frame is noise and is subtracted from the image automatically. On my Canon Rebel XSi 450D it is called "Long Exposure Noise Reduction", found in the custom function settings. Turn it on.

You’ll need an external trigger mechanism that’ll take continuous 30 second shots. On amazon.com I found "Timer Remote Control RS-60E3 For Canon XS XSi T1i XT XTi" for $16.95. Does the same job as the those $150 units.

To avoid dew, I'll hit the camera at least once an hour with a hair dryer. Again, between shots.

After a nights worth of images, upload these jpeg images from your camera to a new folder on your computer. Now I used "auto level" in PhotoShop Elements to clean up each of my jpeg images. For your first attempt, you may not want to use anything.

Next, you’ll need QuickTime Pro. Simply download QuickTime and purchase the registration for $29.99. From QuickTime Pro, select File->Open Image Sequence, browse to the new folder, select the first image in it, and specify the numbers of frames per second. I used 12 frames per second. Once the images are loaded, you’ll have a new window. From there, you can select File->Export. Under Export, Movie to MP4, select the Options button. Set the file format MP4, not MP4 (ISMA). Set the video format to MPEG-4 Improved. Set the data rate to 512 Kbytes/sec. Set the image size to custom, 725x483, preserve aspect ratio using fit within size. Set the frame rate to current, the key frames to 12 frames.

Is anyone familiar with these options? My videos are still coming out a little grainy. The camera produces 4272x2848 images, but if I try to save the video at that size I'll get a 12Mb file. I need to figure out is how to reduce the file size, yet avoid the grainy images.

It would be nice if PhotoShop elements had a batch mode, so I could clean up all the images automatically. Maybe there’s some settings in my Canon I could try so I wouldn’t need PhotoShop elements. In the custom function menu is "High ISO speed noise reduction". I’ll try that next time.

Another thing I might try is taking RAW images. I have not installed my Canon software yet, so maybe there’s a way of handing a batch of RAW images. If anyone knows of a good application, let me know.

I could also try to take continuous 30 second shots without dark subtraction. There would be no 30 second pause between shots, thus doubling the number of shots. After a session, I’d have to take a 30 second shot with the cap on. Then I’d have to manually subtract this image out of all my images.

On a previous attempt, I didn't use the hair dryer. The camera got covered in dew about halfway into the night. Does anyone know of a good battery operated dew-zapper for a DSLR? I tried to find something with Google, but all I saw was homemade units.

If anyone else has any suggestions for settings, software, etc., let me know. This is a work in progress.

July 30, 2011, Earth rotating

Here is my first attempt at keeping the star field fixed. Used Picture Window Pro, composite tool, operation registry. Anchored on the first image, shifting subsequent images. A lot of hard work. If I ever try it again, I'll triple the original the original work area. I wonder how the clip would look if we started the anchor on the last image instead of the first?

If anyone wants to try these techniques, I still have the original images available on CD. If you want to see other attempts at time-lapse, see Randy Halverson's Milky-Way masterpiece or work done from the VLT in Chile.

Spring 2012

This spring I've been taking more time-lapse videos. You can see the current collection by clicking here. I also went back and redid my July 30, 2011 and August 28, 2011 clips. When I "auto level" my images in PhotoShop Elements, I now save them at the highest resolution (let QuickTime do the downsizing). In QuickTime, under Export, Movie to MP4 I tried setting the image size to 1280x720HD and increased the data rate to 1024 Kbytes/sec. This increased the size of the videos, but still smaller than a single high resolution image. Still a little grainy, but better.

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This web page was last updated 04/27/12