Principles for Locating the Image
We can predict the position and size of the image by geometrical construction
We look at a few special rays, and use the principle:
All light rays starting from a given point of the object, are converging in one point (the image point)
Consequence: Following two rays are sufficient to construct the image
- The path of three light rays are easy to construct (we use these)
1. along radius (coming back on itself) 2.parallel to optical axis (through focal point)
3. through focal point (parallel to optic axis)
- Additional principle: the image of a point on the optic axis is on the optic axis