Convex vs Concave
One slider drives both lenses. Watch the difference.
Object distance30.0 cm
Convex (f = +15 cm)
Concave (f = −15 cm)
| Property | Convex | Concave |
|---|---|---|
| Image nature | real | virtual |
| Orientation | inverted | erect |
| Size | same | diminished |
| Magnification | -1.00 | 0.33 |
| Image distance v | 30.00 cm | -10.00 cm |
| Application | Terrestrial telescope (equal-size relay) | Spectacles for myopia |
At a glance
- A convex lens can form both real and virtual images depending on object position.
- A concave lens always forms a virtual, erect, diminished image — regardless of object position.
- Convex magnification varies widely; concave magnification stays between 0 and 1.