This test was done with the Canon EOS 7D using the USB interface of the Timelapse+. For the first time as of today, the Timelapse+ can now control the bulb duration of the EOS 7D and similar cameras without requiring an additional shutter cable. The benefit of this is a simpler setup and more accurate ramping (no flicker at all!).
The images were batch processed in Lightroom with the same develop setting applied to all of the images. There were no deflicker or transitions applied -- you're seeing the ramp transition as produced by the Timelapse+.
The Timelapse+ was set to Auto Bulb Ramp with an interval of 40 seconds (so I wouldn't need as high an ISO in the night) and the integration time was set to 20 minutes. The starting Tv was 1/20. The camera was locked to f/22 (lens twist) and set to ISO 100 to begin with.
There was no intervention after starting the time-lapse -- I just left it up on the roof and went and got it 4 hours later! It would have gone a little longer, only I forgot to put a fresh battery in the 7D so it shut down a little prematurely. Still, it was long enough to prove it's working!
I was finally able to get the USB to control the bulb of the 7D after borrowing a USB analyzer to see what Canon's EOS Utility is doing... The method I was using previously (from online research) worked with the 5DmkII, but not many others. I'm still waiting to hear how it does on more cameras, but I'm quite hopeful since the 7D had been a difficult one previously.
Made with the Timelapse+