Camera FoV Calculator: Using Lens EFL, Distortion, and an Image Sensor

Camera Field of View Calculator

This calculator provides the camera's field of view based on an image sensor and a lens. The field of view of a camera is dependent upon the focal length of the lens, the image sensor size, the lens distortion, and the image circle.

Understanding how different focal lengths affect the field of view is crucial. Focal lengths and distortion can alter the dimensions of the captured scene, impacting the number of pixels and angular resolution across an object which your computer vision.

For wide angle lenses, distortion also changes the aspect ratio of the an object. For our M12 lenses and C-Mount lenses, we also have an FoV calculator which already has the distortion included.

Camera field of view diagram

How to Use the Field of View Calculator

First, input the effective focal length of your lens. Then, input the number of pixels and pixel size of your camera sensor. You can then modify the distortion of the lens to see the impact on field of view.

Advanced users can use the distortion slider to "backsolve" for wide FoV lens distortion. This can then be input to different sensor sizes to calculate the FoV accurately with distortion. 

The primary inputs to our calculator are:

1.) The effective focal length of the lens (EFL) The EFL of a lens is a first order optical parameter. It should not be confused with the Back Focal Length (BFL) or the Flange Focal Distance (FFD) which are mechanical parameters.

2.) The image sensor active area: The image sensor active area is calculated by using the pixel size and the total number pixels in the resulting image/video. If the output image or video is cropped, the field of view will change.

3.) The relative illumination of a lens: The relative illumination is the reduction of light transmitted through a lens, as a function of position in image space. The camera industry loosely uses the term “Image Circle” as the position in image space where relative illumination is ~50%.

4.) The distortion of a lens: Lens distortion is an aberration that represents a change in focal length versus field of view. Distortion is common in wide angle and fisheye lenses, but can occur in normal field of view lenses. The change in focal length over field of view results in magnification differences as the field of view increases, resulting in straight lines that appear to bend.

The FoV Calculator:

Understanding Camera FoV Results

Lens Focal Length and FoV

The lens focal length is fundamental to the field of view. A shorter focal length provides a wider field of view, making it suitable for capturing expansive scenes. On the other hand, a longer focal length offers a narrower field of view, ideal for focusing on specific details or distant subjects.

 A shorter focal length, such as 2mm, provides a wider field of view, allowing you to capture expansive scenes. A longer focal length, like 50mm, offers a narrower field of view, which is perfect for zooming in on distant subjects.

When reducing the field of view, the EFL will become longer. This results in a shallower Depth of Field and Depth of Focus if the same F# is used. So, when considering tradeoffs in field of view you will also need to consider the impact on DoF, which our Depth of Field Calculator is useful for.

Camera FoV Equation

Sensor Size and FoV

The sensor size of the camera is also a critical input for the field of view. A sensor with a smaller format size than the lens will result in an acceptable image. A sensor with a larger format size than the lens format size will result in vignetting with dark or black corners.

A larger sensor size will provide a wider field of view for the same lens, capturing more of the scene. Conversely, a smaller sensor size will result in a narrower field of view.

The crop factor, which is the ratio of the sensor size to a standard full-frame sensor, further impacts the FoV. A larger crop factor means a narrower FoV, effectively magnifying the image. Understanding how sensor size and crop factor affect your FoV can help you choose the right camera and lens combination for your camera hardware design project.

Angular Resolution and IFoV

The Angular Resolution expresses the number of pixels per degree that the imaging system can see. This can be useful to easily convert into the number of pixel across a target at specified distance. The angular resolution is dependent on the magnification of the system, therefore also dependent on the distortion. 

Working on a camera hardware project? Contact our US-based team to discuss your requirements.

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Find other M12 lenses by browsing below our using our M12 Lens Calculator with FoV Calculations.

215°@6.8mm M12 Fisheye Lens
215°@6.8mm M12 Fisheye Lens

CIL220-F2.3-M12BNIR

$39.00
$0.00
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190°@6.4mm Fisheye Lens
190°@6.4mm Fisheye Lens

CIL281-F1.8-M12A650

$59.00
$0.00
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Wide-Angle 4mm M12 Lens
Wide-Angle 4mm M12 Lens

CIL339-F1.6-M12B640

$99.00
$0.00
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No Distortion 3.2mm Lens
No Distortion 3.2mm Lens

CIL034-F2.3-M12A660

$39.00
$0.00
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No Distortion 6mm M12 Lens
No Distortion 6mm M12 Lens

CIL062-F2.8-M12A650

$29.00
$0.00
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IR Corrected 12mm M12 Lens
IR Corrected 12mm M12 Lens

CIL122-F2.0-M12A650

$59.00
$0.00
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Telephoto 35mm M12 Lens
Telephoto 35mm M12 Lens

CIL350-F2.4-M12A650

$59.00
$0.00
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Telephoto 50mm M12 Lens
Telephoto 50mm M12 Lens

CIL051-F2.8-M12ANIR

$70.00
$0.00
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Q: What is an M12 lens (S-mount lens)?

Answer: An M12 lens is a compact lens with a 12 mm thread diameter, often called an S-mount lens. These lenses screws into a camera’s M12 lens mount and are commonly used in board-level cameras for embedded vision systems. M12 lenses are smaller than C/CS-mount lenses, making them ideal for space-constrained applications like robotics​.

Q: What cameras can I use M12 lenses with?

A: There are many embedded vision cameras and AI cameras that are compatible with M12 leness. As long as camera's lens holder is compatible with the mechanical dimensions of the lens, the lens should focus! Please make sure to match the image circle, FoV, and resolution.

Q: How do you focus an M12 lens?

Answer: Use focus targets, then slowly thread the lens while displaying a video. Go past focus, then come back to focus. You can view our full article on how to focus camera lenses.

FAQ

Q: What is a camera’s field of view?

A: A camera’s field of view (FoV) refers to the area visible through the camera’s lens and sensor. It is determined by the focal length of the lens and the size of the image sensor. A wider field of view captures more of the scene, while a narrower field of view magnifies the subject and reduces the visible area. Our Camera Field of View Calculator helps determine the FoV for different lenses and sensor sizes