CCTV Lens FOV Calculator

Calculator Inputs

Sensor preset

Sensor width (mm)

Sensor height (mm)

Focal length (mm)

Crop or digital zoom factor

Target distance

Distance unit

Output unit

Resolution width (pixels)

Resolution height (pixels)

Edge safety margin (%)

Desired density (px/m)

Target scene width (output unit)

Target scene height (output unit)

Mounting height (output unit)

Target plane height (output unit)

Down tilt angle (degrees)

Example Data Table

Sensor	Lens	Distance	Resolution	Approx width	Approx height	Approx density
1/2.8 inch	2.8 mm	10 m	1920 x 1080	20.00 m	11.25 m	96 px/m
1/2.8 inch	4 mm	15 m	3840 x 2160	21.00 m	11.81 m	183 px/m
1/1.8 inch	12 mm	30 m	3840 x 2160	18.00 m	10.13 m	213 px/m

Formula Used

The calculator treats the CCTV lens as a rectilinear lens model.

Effective focal length = physical focal length x crop factor.
Horizontal FOV = 2 x atan(sensor width / (2 x effective focal length)).
Vertical FOV = 2 x atan(sensor height / (2 x effective focal length)).
Scene width = 2 x distance x tan(horizontal FOV / 2).
Scene height = 2 x distance x tan(vertical FOV / 2).
Pixel density = image pixels / real scene dimension.
Required focal length for density = density x distance x sensor size / pixels.

How to Use This Calculator

Select a sensor preset or choose custom dimensions.
Enter the focal length shown on the camera lens.
Add target distance and choose the measurement unit.
Enter the camera resolution in pixels.
Use margin when targets should stay away from frame edges.
Add target size when you need reverse lens guidance.
Add mounting height and tilt for ground reach estimates.
Press Calculate and review the result above the form.

CCTV Lens Planning Guide

A CCTV lens controls how much space a camera can see. It also controls how much detail remains inside that space. A wider lens shows more area, but each person or vehicle gets fewer pixels. A longer lens narrows the scene, yet it improves detail at the chosen distance. This calculator helps compare both effects before installation.

Why Field of View Matters

Field of view is not only an angle. It becomes a real scene width and height at the target distance. That makes lens selection easier. You can check whether a doorway, gate, aisle, counter, yard, or parking bay fits inside the frame. You can also see whether the selected resolution supports the desired evidence level.

Sensor and Lens Relationship

The sensor size and focal length work together. A larger sensor gives a wider view with the same lens. A shorter focal length also widens the view. The calculator uses sensor width, sensor height, focal length, and distance. It then estimates horizontal, vertical, and diagonal angles. It also converts those angles into usable coverage dimensions.

Pixel Density Planning

Pixel density shows how many pixels cover one meter or foot. This value is important for surveillance design. Low density may only show movement. Higher density can support recognition or identification. The calculator compares horizontal and vertical density, then reports the weaker value. This is useful because the weakest direction usually limits image detail.

Advanced Installation Checks

Real cameras are often mounted above the target area. The tilt option helps estimate ground reach when the camera looks downward. This is useful for entrances, loading docks, fences, and corridors. The margin option also helps keep important targets away from image edges. Edge areas can suffer from distortion, blur, glare, or poor focus.

Better Design Decisions

Use this tool to test several lenses before buying hardware. Compare common focal lengths, such as 2.8 mm, 4 mm, 6 mm, and 12 mm. Change distance and resolution to see how coverage changes. For critical evidence, confirm results with real camera specifications and a site test. Lens calculators give strong estimates, but exact views can vary by model, distortion, and focus setting.

Record assumptions too, because future service teams need clear notes.

FAQs

What does CCTV field of view mean?

It is the visible area captured by the camera. It includes horizontal, vertical, and diagonal angles. At a known distance, those angles become real scene width and height.

Does a shorter lens always show more area?

Yes, a shorter focal length usually gives a wider view. It also lowers pixel density because the same pixels cover more space.

Why does sensor size matter?

A larger sensor captures a wider view with the same focal length. That is why two cameras can show different views with the same lens marking.

What is pixel density?

Pixel density is the number of image pixels covering one meter or foot. Higher density gives more detail for faces, plates, and small objects.

What does the crop factor input do?

It narrows or widens the effective view. Use it for digital zoom, cropped sensor modes, or any multiplier that changes the effective focal length.

Can this calculator choose a lens for identification?

It can estimate the minimum lens needed for a desired pixel density. Use the result as a planning guide, then confirm on site.

Why add an edge safety margin?

Important targets should not sit on the edge of the frame. Edges may show distortion, blur, glare, or weaker focus.

Are the results exact for every camera?

No. Lens distortion, focus, sensor crop, housing glass, and manufacturer design can change the real view. Always verify critical projects with the camera datasheet.