Archetypes for curved mirrors
To summarize, there are just three distinct possibilities for images of a real object produced by a
- Converging mirror (f positive) with object farther away than the focal point
(d0 > f):
Image is real and inverted (examples: Reflecting telescope, Satelite dish).
- Converging mirror (f positive) with object closer than the focal point
(d0 < f: image is virtual, upright, enlarged (example: shaving mirror).
- Diverging mirror (f negative): image is virtual, upright, "smallified"
(examples: garden ball, curved automobile rear-view mirror, safety mirrors at IM East)
These three possibilities can easily be derived by making sketches or by using the equations
1/di + 1/do = 1/f
M = -di / do .