a wide-angle lens

In photography a wide-angle lens is a lens whose focal length is dramatically smaller than the focal length of a normal lens for a given film plane. A normal lens will have an angle view between 40° and 50° while a wide-angle lenses have an angle view that is much bigger.

The wide-angle lens allows more of the scene to be included in the photo, which means this type of lens is very useful for architectural, interior and landscape photography where the photographer may not be able to move backwards from the scene to photograph it all. Another may use for a photographer for this type of lens is if the photographer wishes to emphasis the different in size/distance between objects in the foreground and background; nearby objects appear very large and objects at a reasonable distance  appear small and far away. This exaggeration of relative size can be used to make the foreground objects more prominent and stand out, while catching the expansive background. 

here are some examples of professional work using a wide-angle lens and what a wide-angle lens looks like;