Security & CCTV
CCTV Lens & Field of View
Sensor size and focal length fix the geometry: scene width at any distance is just distance x sensor width / focal length.
Calculator
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How it works
Pick the sensor format (widths: 1/4" 3.6 mm, 1/3" 4.8 mm, 1/2.8" 5.4 mm, 1/2" 6.4 mm), enter the focal length and distance. HFOV = 2 x atan(sensor / 2f). Add a wanted width to get the focal length that achieves it.
Frequently asked questions
What does a 2.8 mm lens see?
On the common 1/2.8" sensor, about 88 degrees horizontally - roughly 19 m wide at 10 m. Wide and short: great awareness, poor identification range.
Fixed or varifocal lens?
Fixed is cheaper and sharper for a known scene; varifocal (e.g. 2.8-12 mm) lets you trade width for reach at commissioning. Calculate both ends before choosing.