Moves the camera along its line of sight.
The buttons on this flyout replace the Zoom button when a camera viewport is active.
A free camera moves along its depth axis in the direction its lens is pointing. Unlike a target camera, its target distance remains fixed, no matter how far you dolly.
Neither free cameras nor free spots have targets. When you activate one of their viewports, the navigation button appears as a flyout, but only Dolly Camera or Dolly Light is available. If you reactivate a viewport belonging to a targeted object, the three choices are again provided.
Dolly Camera: Choose this option and drag the mouse to move only the camera to and from its target. If you go past the target, the camera flips 180 degrees and moves away from its target.
Dolly Target: Choose this option and drag the mouse to move only the target to and from the camera. This causes no visual change in the camera viewport, unless you dolly the target to where it passes through the camera to the other side, at which point the camera view is reversed. However, changing the relative position of the target to the camera affects other adjustments, such as Orbit Camera, which uses the target as its rotational pivot.
Dolly Camera + Target: Choose this option and drag the mouse to move both the target and the camera to and from the camera.