The camera controls expand when the icon in the top right is clicked.
Controls in red text seem to be used less often. Tilting the camera is comparable to holding your camera at a 45° angle. Zooming in is fairly predictable, but zooming out produces stretching effects that are present in the final render - fisheye lens.
The centre control moves the camera parallel to the ground plane.
Clicking any of the control icons resets the value to zero - or 1000 in the case of altitude.
Zooming out (top) Moving camera back (bottom)