CURRENT BUILD: .241028 (Located in top right corner of main screen)
There are now two camera modes: Standard and Fixed. Standard follows the rotation of the ship, and fixed does not. You can switch between them with Left Alt. MMB should return the camera to the rear of your ship in either mode.

Rotation lag is on by default but is very fast and should not be noticeable. You can disable it still but free look will be less smooth.