The ability to rotate the camera at any angle is one of the (practically) unique features of the Asus Zenfone 6 and today’s update should make the experience better. In fact, most of the items on the changelog for version 16.1220.1906.167 are camera-related.
First off, after the update the camera should rotate at a constant speed and should complete the full 180° rotation (some users experienced slow and incomplete rotation). Also, the Retract camera button is now more accessible (it’s on the 1st page of the quick settings).
Then there are a number of image quality improvements. The electronic image stabilization (EIS) was tuned to work better for video recording. Super Night Mode was tweaked to produce better texture (thanks to improved noise reduction) and render more accurate colors.
Additional changes promise reduced power usage and increased call quality. Last but not least are the usual system stability improvements.
The firmware will be delivered over the air in several batches (depending on serial number), so you it may take a few days before you see it. You can check manually by tapping System updates in Settings > System.