Lens Focal Length Calculator
Lens Focal Length
Calculate focal length from object and image distances.
Formula
1/f = 1/object_distance + 1/image_distance
Frequently Asked Questions
What is the thin lens equation?
1/f = 1/do + 1/di where f is focal length and d is distance.
What does a shorter focal length mean?
A shorter focal length means a stronger, more converging lens.