This Camera Focal Length Calculator finds the Lens Focal Length From a Field of View

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.

Building a Camera? Use Our Wide-Angle Lens Calculator or Browse Below

Aerial Robotics?

Our light-weight, miniature lenses are ideal for collision avoidance, long-distance viewing, and end-customer viewing.

Small 2.1mm M12 Lens

CIL821-F2.4-M12B650

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
$39.00

Large Format 3.5mm M12 Lens

CIL334-F2.2-M12A660

3.5mm M12 Lens for IMX226 AR0821 IMX537
3.5mm M12 Lens for IMX226 AR0821 IMX537
S-Mount Drone Lens for Wide Angle IMX226
Wide Angle Drone Lens for IMX226
$39.00

Wide-Angle 3.5mm M12 Lens

CIL335-F1.8-M12A660

3.5mm Wide-Angle M12 Lens
3.5mm Wide-Angle M12 Lens
3.5mm Wide-Angle S-Mount Lens
Wide-Angle M12 Lens CIL335
$49.00

Surveillance?

Our low F#, high resolution lenses are suitable for 180° dome cameras, low light, and active IR illuminated scenes.

200°@5.7mm IP67 Fisheye M12 Lens

CIL217-F2.0-M12A650

Mini Fisheye S Mount Lens
Mini Fisheye S Mount Lens
Tiny Fisheye Lens
Miniature Fisheye
$39.00

F-Θ Wide-Angle 4.4mm M12 Lens

CIL344B-F2.7-M12A655

Wide Angle M12 Lens
Wide Angle M12 Lens
Wide Angle S-Mount Lens
AR0820 M12 Lens
$49.00

Telephoto 35mm M12 Lens

CIL350-F2.4-M12A650

35mm M12 Lens
35mm M12 Lens
35mm Board Mount Lens
35mm S Mount Lens
$59.00

Surveillance?

Our low F#, high resolution lenses are suitable for 180° dome cameras, low light, and active IR illuminated scenes.

Consumer / AR+VR?

Our high resolution fisheye lenses will let you design 360° cameras and and stereographic lenses are equivalent to "GoPro" lenses.

230°@4.5mm Fisheye M12 Lens

CIL213-F2.3-M12A660

230 degree M12 Fisheye lens
230 degree M12 Fisheye lens
Ultra-wide fisheye lens with 230 degree field of view
230degree mini fisheye lens
$119.00

Low Distortion 2.6mm M12 Lens

CIL028-F2.4-M12IR

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.
$39.00

GoPro 3.0mm M12 Lens

CIL331-F2.5-M12A660

3.1mm Wide Angle M12 Lens
3.1mm Wide Angle M12 Lens
3mm S-Mount Lens
3mm M12 Lens
$39.00

Video Conferencing?

Our wide-angle, low distortion, high resolution M12 lenses result in optimal object deformation without post-processing.

Low Distortion 1.8mm M12 Lens

CIL018-F2.8-M12IR

135° 4K+ low distortion M12 lens for IMX335 and AR0521
135° 4K+ low distortion M12 lens for IMX335 and AR0521
135° low distortion S-Mount Lens
No Distortion Wide Angle M12 Lens
$39.00

Low Distortion 2.6mm M12 Lens

CIL028-F2.4-M12IR

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.
$39.00

No Distortion 3.3mm M12 Lens

CIL033-F2.6-M12IR

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
$39.00

Video Conferencing?

Our wide-angle, low distortion, high resolution M12 lenses result in optimal object deformation without post-processing.

Mobile Robotics?

Find a low F# or low distortion lens to optimize your computer vision framerate.

Low Distortion 2.2mm M12 Lens

CIL023-F1.8-M12IR

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
$39.00

Wide-Angle 3.5mm M12 Lens

CIL335-F1.8-M12A660

3.5mm Wide-Angle M12 Lens
3.5mm Wide-Angle M12 Lens
3.5mm Wide-Angle S-Mount Lens
Wide-Angle M12 Lens CIL335
$49.00

Fast 6mm M12 Lens

CIL061-F1.8-M12A650

6mm M12 Lens for S-mount cameras
6mm M12 Lens for S-mount cameras
6mm M12 Lens for FLIR and AR0234
6mm Lens for IMX290
$39.00