This Camera Focal Length Calculator finds the Lens Focal Length 

Camera Lens Focal Length Calculator

A Camera Focal Length Calculator. This Calculates a Lens EFL for Cameras.A Camera Focal Length Calculator. This Calculates a Lens EFL for Cameras.

This effective focal length calculator helps you select a lens to use with your camera. The calculator takes your target field of view (angle of view) and camera specification then provides the required lens EFL.

The calculator uses the camera lens focal length equation. This formula is different than the lens maker's equation which is intended for simple thin lens elements.

The Optical Effective Focal Length (EFL) should not be confused with the Mechanical Back-Focal Length (BFL). The EFL determines the field of view of the camera while the BFL determines whether a lens will focus on a camera.

Read Our Camera Calculator & Optics Design Page, or Click below Use our Other Camera Calculators

Camera Field of View Calculator. FoV Calculator
Camera Depth of Field Calculator. DoF Calculator.
Camera Angle of View Calculator for Camera Lens Selection. AoV Calculator.

Find a Lens For Your Project Using Our M12 Lens List Or By Clicking Below

A 14MP 4mm M12 lens that is wide angle no distortion.
A 14MP 4mm M12 lens that is wide angle no distortion.
A 3.9mm M12 Lens pictured with the Raspberry Pi High Quality
A 4K M12 Lens for the Raspberry Pi High Quality Camera. CIL039.
14MP 4mm M12 lens on IMX178
CIL039-F2.4-M12IR
No Distortion 3.9mm M12 Lens
$39.00
A 12MP+ 4mm S-Mount Lens
A 12MP+ 4mm S-Mount Lens
A No Distortion 4.3mm S Mount Lens
A 14MP 4.3mm M12 Lens CIL043
CIL043-F3.0-M12IR
No Distortion 4.3mm M12 Lens
$39.00
A 6mm M12 lens for 4K+ sensors
A 6mm M12 lens for 4K+ sensors
A 6mm cctv lens for raspberry pi HQ
A 6mm S-Mount lens for 1/1.8
Low Distortion 6.0mm M12 Lens
CIL060-F2.8-M12IR
Low Distortion 6.0mm M12 Lens
$39.00
The CommonLands CIL081-F1.8-M12NOIR is a 8mm F/1.8 S Mount M12 Lens for cameras such as the Raspberry Pi HQ Camera.
The CommonLands CIL081-F1.8-M12NOIR is a 8mm F/1.8 S Mount M12 Lens for cameras such as the Raspberry Pi HQ Camera.
An 8mm S-Mount Lens for Board Mount Cameras
The CommonLands CIL081-F1.8-M12NOIR 8mm M12 lens is pictured with the FLIR IMX226 camera.
CIL081-F1.8-M12NIR
Large Format 8.0mm M12 Lens
$49.00
Telephoto 12mm M12 Lens
Telephoto 12mm M12 Lens
Telephoto M12 Lens 12mm
Telephoto 12mm M12 Lens for Arducam 1/1.8
Telephoto 12mm S-Mount Lens
CIL125-F2.4-M12IR
Telephoto 12.5mm M12 Lens
$29.00
A 5MP+ 16mm M12 lens for the Raspberry Pi High Quality Camera and other 5MP+ cameras.
A 5MP+ 16mm M12 lens for the Raspberry Pi High Quality Camera and other 5MP+ cameras.
A 16mm M12 lens with the Raspberry Pi High Quality Camera.
A 16mm M12 lens assembled with the Raspberry Pi High Quality Camera.
CIL160-F2.0-M12NOIR
Telephoto 16.0mm M12 Lens
$39.00
25mm M12 Lens
25mm M12 Lens
25mm S Mount Lens
25mm lens for FLIR Cameras
CIL260-F2.0-M12IR
Telephoto 26mm M12 Lens
$49.00
An M12 GoPro Fisheye Lens | 2.8mm M12 Lens
An M12 GoPro Fisheye Lens | 2.8mm M12 Lens
A miniature Rpi wide-angle Lens | A 2.8mm S-mount Lens
A GoPro Fisheye Lens for the Raspberry Pi | A 2.8mm M12 Lens
CIL026-F2.4-M12IR
GoPro 2.8mm M12 Lens
$39.00
A 4mm M12 Lens which is 14MP and F-theta | CIL340
A 4mm M12 Lens which is 14MP and F-theta | CIL340
A wide-angle 4mm S-Mount Lens
4mm Wide-Angle M12 Lens CIL340
4mm Wide Angle M12 Lens
CIL340-F2.0-M12IR
F-Θ Wide-Angle 4.0mm M12 Lens
$65.00
8mm 1/1.7
8mm 1/1.7
8mm S-Mount Lens for 4K+ sensors
8mm M12 Lens for 12MP+ 1/1.7
CIL080-F1.8-M12IR
F-Θ Mid-Range 8.0mm M12 Lens
$29.00
Low Distortion Wide Angle M12 Lens 2mm
Low Distortion Wide Angle M12 Lens 2mm
Wide Angle Low Distortion 2mm S-Mount Lens CIL023
2mm M12 Lens Low Distortion
2mm M12 Lens Wide Angle No Distortion
CIL023-F1.8-M12IR
Low Distortion 2.2mm M12 Lens
$39.00
2.7mm M12 Lens for IMX226
2.7mm M12 Lens for IMX226
A 2.7mm M12 Lens for S-Mount FLIR
Arducam IMX477 2.7mm M12 Lens
CIL027-F2.8-M12IR
Low Distortion 2.7mm M12 Lens
$39.00
A wide angle 2.8mm M12 lens no distortion.
A wide angle 2.8mm M12 lens no distortion.
A 2.8mm M12 lens with a wide angle and no distortion for the RPi HQ Camera.
A wide angle no distortion 2.8mm S Mount Lens.
Low Distortion 2.8mm M12 Lens
CIL028-F2.4-M12IR
Low Distortion 2.8mm M12 Lens
$39.00
A 3.3mm M12 lens that is wide angle no distortion.
A 3.3mm M12 lens that is wide angle no distortion.
A 3.3mm S Mount lens for the Raspberry Pi High Quality Camera.
A 3mm FLIR camera lens. A wide angle no distortion M12 Lens
3mm S Mount Lens with Arducam
No Distortion 3.3mm M12 Lens
CIL033-F2.6-M12IR
No Distortion 3.3mm M12 Lens
$39.00
A 2.1mm M12 Lens for 1/3
A 2.1mm M12 Lens for 1/3
Tiny Pinhole Lens for S-Mount Cameras
15mm TTL Short M12 Lens for Surveillance
CIL821-F2.4-M12IR
Small 2.1mm M12 Lens
$39.00
Short Compact 3.6mm M12 Lens CIL036
Short Compact 3.6mm M12 Lens CIL036
Compact 3.6mm M12 Lens CIL036
Compact 3.6mm S Mount Lens CIL036
CIL036-F2.0-M12IR
Small 3.6mm M12 Lens
$39.00