# Summary ray diagrams

At 2F (at two principal focal lengths).

At 1F (at one principal focal length).

At greater than 2F (at more than two principal focal lengths).

Between 2F and F (between two principal focal lengths and one principal focal length).

Between F and lens (between one principal focal lengths and the lens).

and a summary in block format would be.

NOTE: The NO is to show that there is nothing in this triangle.