Which type of camera movement allows an operator to elevate or lower the camera smoothly?

The correct choice is the type of camera movement known as a pedestal. This movement involves raising or lowering the camera on its pedestal or tripod, allowing for smooth vertical adjustments without changing the angle at which the camera is facing. Pedestal movements are particularly useful for following action or changing perspectives without losing composition or focus on the subject.

In contrast, a pan involves rotating the camera horizontally from a fixed position, which does not allow for elevation or lowering of the camera. A tilt refers specifically to moving the camera up or down while keeping the base stationary, but it is generally about adjusting the angle rather than changing the overall height. Roll involves rotating the camera on its axis, creating a tilt effect that can give a dramatic feeling but does not involve elevating or lowering the camera's position. Hence, pedestal is the movement that specifically caters to the up-and-down adjustment, making it the right answer in this context.