Science & Engineering · Optics, Photonics & Acoustics
Thin Lens Equation Image Distance, Diopters & Magnification Calculator: inputs, method, and how to read the result
Solve the Gaussian thin-lens equation for real/virtual image distance and magnification.
Choose inputs for the case you are checking
The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.
- Focal Length Mm: Lens focal length (f) in millimeters (+ converging, − diverging).
- Object Distance Mm: Object distance from optical center (d_o) in millimeters.
- Object Height Mm: Physical object height in millimeters.
What the calculation includes
With the default values shown, Image Focal Distance (d_i) is 62.5 mm. The calculation follows Thin Lens & Magnification Physics & Engineering Equation; the formula and variable definitions above show how the inputs combine.
One-input check: With the other defaults held constant, changing Focal Length Mm from 50 mm to 55 mm changes Image Focal Distance (d_i) from 62.5 mm to 70.51 mm. This is a comparison inside the calculator's stated model, not a prediction.
Where to use caution
- Uses standard SI physical constants (g = 9.80665 m/s², c = 299,792,458 m/s, σ = 5.670374×10⁻⁸ W·m⁻²·K⁻⁴).
- Engineering reference model; apply appropriate safety factors and empirical calibration for critical hardware designs.
Scope: SI / NIST Physics & Engineering Standard Check the assumptions and limitations against your situation before relying on the estimate.
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