Perspective relations Objects appear to be smaller the further away they are - of course, they may actually be very large. Your eyes constantly feed you information about object distance, by the reflection of light rays. These are perspective relations.
Camera lenses operate in a similar way.
However, lenses can be changed, giving different possibilities of rendering perspective relations. The focal length alters perspective relations in the shot. Three types of lenses convey different relations. This alters perception, and makes the viewer think that there is more space than there actually is. A tiny room can appear to be much larger.