The focal length f´ virtually serves to calculate the required lens and is thus the most important specification to characterise an (entocentric) normal lens.

Equivalentfocallengthcalculator

Onion's fork of OpenWRT's source build system. The firmware for the Omega2, Omega2+, and Omega2 Pro is based on the openwrt-18.06 branch.

The theoretic value of the focal length calculation serves to find the best suitable optics. Typical increments of focal lengths for C-mount lenses are e.g. (1.8, 2.8, 4, 6,) 8, 12, 16, 25, 35, 50 and 75 mm.