GBTimelapse now supports the Dynamic Perception MX3 Motion Controller. With GBT support, the MX3 can do bulb control as short as 0.033 seconds. It's easy to install the special firmware, and it's totally compatible with the standard MX3 1.08 firmware.
Before you can use the Dynamic Perception MX3 controller with GBTimelapse you must first install two Windows drivers and then upload the GBTimelapse firmware. Don't worry, it's will only take a few minutes to setup.
If you don't understand why bulb shooting is so important, please watch this video too. It explains the workings of a SLR shutter and how that leads to shutter flicker. And it discusses how using bulb mode is superior for time-lapse and how to eliminate any bulb mode problems related to the shutter mechanism. Also explains how GBTimelapse' AutoRamp works with bulb mode to realize the holy grail of a flicker free day to night time-lapse. (Slow Motion shutter by Adam Shomsky)