Front Focal Length Calculator

Posted by Dinesh on 20-06-2019T18:35

Calculate front focal length (FFL) by using simple optical calculator online.

The distance from the front focal point of the combined lenses to the first lens is called the front focal length (FFL).

If d tends to zero, the focal lengths tend to the value of f given for thin lenses in contact.

If the separation distance is equal to the sum of the focal lengths (d = f₁+f₂), the FFL and BFL are infinite.

Calculation of Front Focal Length

$F F F = \frac{f_{1} (f_{2} - d)}{(f_{1} + f_{2}) - d}$

where,

f₁ = Focal length of one of the lenses (m)

f₂ = Focal length of the other one of the lenses (m)

d = Distance between the lenses (m)

FFL = front focal length (m)