UPDATE: Firmware released by Panasonic has now fixed this problem. You can download the update at panasonic.net/avc/lumix/pressrelease/gh3_lens_firmware/
We are discussing this issue (and other issues) with the GH3 in the timelapse.org forums (timelapse.org/forums/threads/gh3-for-timelapse-so-far.370/) Hope you'll stop on by to check out some timelapse tutorials, share your timelapse, and watch other great timelapse from around the world.
UPDATE: Another test using a longer shutter time yields equally weird results: timelapse.org/forums/threads/gh3-for-timelapse-so-far.370/#post-1270
The GH3 is a wonderful camera. And it has great potential for use as a timelapse camera once a few issues get sorted out. For a lot of timelapse, people will use an external intervalometer or motion control rig to control the shutter release on the GH3. But when shooting a static shot, or shooting a hyperlapse, the intervalometer built into the GH3 is the best solution. Or at least it would be... if it worked correctly. It doesn't.
For this test, the GH3 was set to manual focus, shutter, and aperture, white balance..... Everything manual. The lens was the Lumix 20mm f/1.7.
The interval was set 5 seconds, and as you will see in the video, the camera's buffer finishes it's write to the memory card in about 1.5 seconds (the card was the great SanDisk Extreme Class 10 45MB/s SDHC card).
The camera SHOULD fire the shutter release every 5 seconds. There is no logical reason for it to fire the shutter more or less than every 5 seconds, and yet it does.
You can contact Panasonic to report this issue at:
Phone: 1-800-211-PANA (7262)
Snail Mail: Panasonic Corporation of North America, Customer Experience Department, 661 Independence Pkwy, Chesapeake, VA 23320