Wide Angle Lens Distortion and Fisheye Lenses

Wide Angle Lenses and Fisheye Lenses: An Introduction

Distortion is the change in magnification and angular resolution as a function of field angle in an image.

Optical Distortion, Wide Angle, and Fisheye are used when discussing lenses that provide a large field of view.

What is Wide Angle? What is Fisheye? Is there really a Difference?

Yes, there is a difference between a fisheye and a wide-angle lens. A definition from the Smith's Modern Optical Engineering, Fourth Edition, page 718, is: 

Fisheye: A lens with a field of view of 180° or more.

Therefore, a Fisheye Lens can be a Wide Angle Lens when an image sensor smaller than the image circle is used.

A Wide Angle Lens is not necessarily a Fisheye Lens.

GoPro's marketing team was stuck with "Fisheye" because the first product used a cropped Fisheye lens. The newer GoPros use Wide Angle lenses which are not Fisheye lenses.

So How Can a Fisheye Lens Be Wide Angle? But Not Vis-Versa?

Fisheye Lenses with 180°+ Field of View do not always provide 180° FoV if used with a smaller sensor.

For example, a Fisheye with Full Coverage can provide much smaller fields of view such as 160° Diagonal, where they act as a "Wide Angle" Lens.

The reason for this is the "Fisheye Fill Factor" which has six different general categories.

Wide Angle vs Fisheye Lens

Insert Image with IMX477: CIL227, CIL220, CIL219, CIL217, CIL213, CIL212

Barrel Distortion as a Third Order Optical Aberration

Optical distortion is a third order transverse aberration. The simple explanation is that distortion is the change in magnification (angular resolution) versus image height.

Distortion is present in all fisheye lenses and most wide-angle lenses.

Additionally, distortion is a function of field angle, and usually increases as field increases.

Rule of Thumb 1: A lens with greater distortion has greater field of view than another lens which has the same Effective Focal Length.
Rule of Thumb 2: The smaller the field of view, the less apparent optical distortion is.

What is the Difference Between Perspective Distortion and Optical Distortion?

Optical distortion is a third order transverse aberration. The simple explanation is that distortion is the change in magnification (angular resolution) versus image height.

Distortion is present in all fisheye lenses and most wide-angle lenses.

Rule of Thumb 1: A lens with greater distortion has greater field of view than another lens which has the same Effective Focal Length.
Rule of Thumb 2: The smaller the field of view, the less apparent optical distortion is.

Why does Distortion Matter to Computer Vision?

Distortion changes the scale of objects at different parts of the field of view. Additionally, the scale changes both radially and tangentially, causing object deformation.

CNN-based methods should ideally be trained on data that has the distortion profile used by your embedded vision system. Otherwise, activations will occur in incorrect locations.

Distortion and Computer Vision

Pei, et. al. "Effects of Image Degradations to CNN-based Image Classification"

Distortion changes the scale radially and tangentially, causing line deformation.

Distortion and Computer Vision

Pei, et. al. "Effects of Image Degradations to CNN-based Image Classification"

Li, et.al. 2020, “ULSD: Unified Line Segment Detection across Pinhole, Fisheye, and Spherical Cameras”​ 

View Other Image Quality and Computer Vision Topics

What's Your Application? Our Optics Cover the Spectrum.

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.

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

IP67+ No Distortion 3.2mm Lens

CIL034-F2.7-M12IP660

IP65 M12 Lens
IP65 M12 Lens
IP67 M12 Lens
IP67 FLIR S-Mount Lens M12 Lens
$49.00

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

No Distortion 4.3mm M12 Lens

CIL043-F3.0-M12IR

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
$39.00

Does it Require an IP65+ Lens?

We offer IP65+ variants of many lenses. These are suitable for applications  exposed to the environment, without a window.

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