๐ Thin Lens Equation Calculator
Any consistent unit works (cm, mm, etc.) โ just use the same unit for both values.
Enter a lensโs focal length and the object distance to calculate the image position (image distance) and magnification using the thin lens equation (1/f=1/do+1/di). Use a positive focal length for a converging (convex) lens and a negative one for a diverging (concave) lens.
How to use
- Enter the focal length (positive for convex, negative for concave).
- Enter the object distance (distance from the lens to the object, always positive).
- The image distance, magnification, real/virtual, and upright/inverted status are calculated automatically.
FAQ
What sign convention does this use?
It uses the Cartesian sign convention: object distance is always positive, focal length is positive for a converging lens and negative for a diverging lens.
What does a virtual image mean?
A negative image distance means the image is virtual โ light rays donโt actually converge there, so it canโt be projected onto a screen (like the image seen through a magnifying glass or mirror).
What does a negative magnification mean?
A negative magnification means the image is inverted (upside down and reversed) relative to the object. A positive magnification means the image is upright.