Create Camera From View creates a Target camera whose field of view matches an active Perspective viewport. At the same time, it changes the viewport to a Camera viewport for the new camera object, and makes the new camera the current selection.
Creating a camera object to match a Perspective view
Alternatively, if the scene already contains a camera and the camera is selected, then Create Camera From View does not create a new camera from the view. Instead, it simply matches the selected camera to the active, Perspective viewport. This functionality was adopted from the Match Camera to View command, which is now available only as an assignable main user interface shortcut (see Keyboard Shortcuts).
To create a camera from a view, assuming any existing cameras are unselected:
3ds Max creates a new camera, matching its view to that of the Perspective viewport, and then switches the Perspective viewport to a Camera viewport, showing the view from the new camera.