Use the following form to calculate the horizontal and vertical field of view
(a rectangular plane) you get with a lens at a specific distance. Input the
distance, input your lens size, and click CALCULATE.
1. The area in FIELD OF VIEW is not necessarily in focus.
2. A fixed-focus lens has a pre-set distance at
which objects are in focus. For a 3.6mm fixed-focus lens that distance is
generally 5-20' from the lens. Objects closer or further than the pre-set
focus distance will be out of focus in proportion to the amount of distance
they are inside/outside of that zone. For flexible focus control use a
camera with a varifocal lens.
This page is provided as a convenient tool for selecting
lenses. Due to the large number of unpredictable factors in every surveillance
environment, the calculation can not be assumed to be exact. Use caution when
selecting a lens. We suggest that you always purchase a lens with a greater
field of view than this calculation indicates.