Performs a combination of FOV and Dolly for either target-cameras or free cameras.
This button replaces the Zoom All button when a camera viewport is active. It increases the amount of perspective flare, while maintaining the composition of the scene.
Hold down the CTRL key to magnify the effect of the mouse on perspective adjustment.
A target camera can pass through its target object while you are using Perspective. When this happens the FOV reaches its maximum angle of 180 degrees at the target location and cursor motion is reversed until you release the drag.
A free camera continues moving along an infinite path but uses an implied target position to control the FOV change rate. This implied target is defined as a point specified by the Target Distance field in the free camera Parameters rollout.