Definitions for "Optical viewfinder"
A viewfinder system that shows a similar view to that seen by the camera lens ( as on 35mm compact cameras ) Useful because it uses no power, but can cause parallax and focus errors.
Through a conventional optical viewfinder, your "picture-to-be" is seen directly. Don't lose sight of the fact that the view from the viewfinder is not exactly the same as what the lens sees. This is very important for close-up shots. It is also recommended to take account of the markings in the viewer.
An eye level viewfinder that is used to compose the photograph.