Took a night shot of Marina Bay, Singapore at 3 seconds exposure and ISO 200. It was taken in JPEG with only slight adjustment in levels and cropping using Photos in my iMac. I am amazed by the stability of the P3P gimbal and camera.
For long exposure shot, remember to turn off the arm's LED light temporarily. Otherwise you will see two red patch in the photo. You can turn the arm's LED light off or on during the flight. To do so, click Mode > MC Settings > Advanced Settings (see pic below).
You will see "Turn on arm's LED light" at the bottom. It is "on" by default (see pic below).
Just slide the tab to the left to turn off the arm's LED light temporarily (see pic below). Remember to turn on after you have finished taking the photos.