A simple lens mimics the human eye's standpoint, in most cases round 50mm in focal duration

https://wiki-cable.win/index.php/The_Pros_and_Cons_of_Third-Party_Camera_Lenses

A essential lens mimics the human eye's viewpoint, in general round 50mm in focal size. This makes it flexible for a large number of pictures types which include pictures, avenue photography, and general snapshots.