Orthographic views are parallel to the scene and offer a more objective view. They focus on two axes at a time and are referred to as the Top, Side and Front views.
In many cases, you will require several views to help you define the proper location of your objects. An objectOs position that looks good in the Top view may not make sense in a Side view. Maya lets you view multiple views at one time to help coordinate what you see.
Perspective view
Orthographic views
Cameras
To achieve a particular view, you look through a digital camera. An orthographic camera defines the view using a parallel plane and a direction while a perspective camera uses an eye point, a look at point and a focal length.