| A | B |
|---|
| Power (lens) | Reciprocal of focal length |
| Diopter | Unit for power (lens) |
| m | Symbol for lateral magnification |
| M | Symbol for angular magnification |
| Focal length | Radius of curvature/2 |
| Object same side of surface as incoming light | s > 0 |
| Image on same side of surface as outgoing light | s (prime) > 0 |
| m > 0 | Erect image |
| m < 0 | Inverted image |
| Center of curvature on same side as outgoing light | R >0 |
| Center of curvature on opposite side as outgoing light | R < 0 |
| Converging lens | f >0 |
| Diverging lens | f <0 |
| f-number | focal length/aperture diameter |
| Cornea | Front curved portion of the eye |
| Liquid behind cornea | Aqueous humor |
| Refracting telescope | Similar to compound microscope |
