As I have been delivering talks and classes I have found this is an effect that many photographers don't know about or don't understand. Lens Foreshortening is sometimes referred to as lens compression - they are the same thing.
Lens Foreshortening Explained
In simple terms : - A wide angle (10mm) lens will make the near object look further away and the distant object much much look far away - compared to the human eye. - A zoom (200mm) lens lens will make the near object look near and the distant object look nearer - compared to the human eye.
Nate Torres has put together a great article on this subject
However here are a couple of videos to explain
If you understand Lens Foreshortening / Lens Compression then you can significantly impact your photography as this will have a massive impact on the relationship of the foreground and the background in your images.