Thin Lens Calculator
Solve the thin lens equation for any variable.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Select which variable to solve for, then enter the other two values in centimeters. The calculator shows the solution along with magnification and image characteristics.
About Thin Lens
The thin lens equation is a cornerstone of geometrical optics. It relates the focal length of a lens to the distances of the object and image from the lens. This equation, combined with the magnification formula, allows complete analysis of image formation by thin lenses. It applies to converging (positive focal length) and diverging (negative focal length) lenses. Applications include camera design, magnifying glasses, projectors, and corrective eyewear.
Frequently Asked Questions
What is the thin lens equation?
The thin lens equation 1/f = 1/do + 1/di relates the focal length (f), object distance (do), and image distance (di). It works for both converging and diverging thin lenses.
What does a negative image distance mean?
A negative image distance means the image is virtual and on the same side as the object. A positive image distance means the image is real and on the opposite side.
How is magnification calculated?
Magnification m = -di/do. Positive magnification means the image is upright (virtual). Negative means inverted (real). Magnitude greater than 1 means enlarged.