Table Mountain with Moon
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The perspective is changed when using a telephoto lens to photograph a specific object. It is not as a result of the focal length that changes the perspective but rather the distance between the camera and the subject that causes this change is perspective. All the focal length really does is change the magnification and viewing angle.
Using a longer focal length requires you to stand further away to capture the same subject and this causes a change in the perspective of the image which results in a change of the background. You can do a test to illustrate this. If you photograph a nearby tree and fill the frame with a wide angle lens and then switch to a telephoto lens (or zoom in) and stand further back to fill the frame again with the same tree you will notice the change in perspective and the change of the background.
This photo was taken in June 2015 with a Canon 5D MkIII, Canon EF 100-400mm f/4-5.6L IS USM on a monopod
Camera Settings: f/5.6, 1/640 seconds and ISO 100