Draw a ray diagram to locate the position of image when a point source (S) is placed on optical axis MN of a convex lens, in such a way that it is beyond focal point (F). See figure.

- Draw a perpendicular line to principal axis passing the focus (F).
- Draw a ray from point source (S) in any direction to meet lens at point §.

- Now draw another line parallel to the ray drawn from the point source (S) and passes through the pole §. This line intersect the normal at point F _{ 0 }.
- Now draw a line passing from point P’ to pass through the point F _{ 0 } such that it meets principal axis at a point (say I).
- T is the image point for the point source (S).