Bramping or Bulb Ramping is the shooting of a timelapse with the shutter speed getting shorter or longer to accomodate the changing light levels.
I was using the Triggertrap app and dongle for the iPhone for this video. This timelapse consisits of 350 seperate photographs. At the start of the timelapse the camera was set to a 1.7s exposure the final image was 1/15s. Unfortunately the camera took a couple of knocks and I was also shooting through a very grubby window which didn't help.
I can see many applications for this altough it will take a little practice for the settingd, I had to adjust the aperture on the camera to prevent the sky blowing out on a couple of occasions, but for a first test, I'm quite happy.