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...
Source: https://www.gsmarena.com/new_update_fixes_asus_zenfone_6_camera_rotation_issues_improves_image_quality-news-38269.php