Question

The formula for the maximum focus range or hyperfocal distance, H, of a camera is given by , H=L^2/f*c where L is the focal length of the lens, f is the setting on the camera to reduce or enlarge the aperture, and c is the diameter of the circle of least confusion. Which of the following expresses this same relationship between the quantities in terms of the focal length of the lens?

Answer 1

We are given the formula
H=L² / f*c
where
H = maximum focus range/hyperfocal distance
L = focal length of the lens
f = setting on the camera to reduce or enlarge the aperture
c = diameter of the circle of least confusion

We are to express the equation with the focal length on the left side.
So,
H f c = L²
L = √Hfc