Choosing the ideal Lens Angle for your Security Cameras
What is a Camera Lens Angle?
A camera’s lens angle refers to the extent of a scene visible through the camera lens, and this is chiefly determined by the lens’s focal length. In simpler terms, it signifies what the camera can capture in its frame. Generally, when a lens with a longer focal length is used, the camera’s lens angle becomes narrower, akin to zooming in on the subject.
Lens angle = Field of View
The lens angle is essentially synonymous with the term “field of view” (FOV), which describes what the camera can see in front of it. This is quantified using angles, with two main measurements: horizontal (H) and vertical (V).
- Horizontal Angle (H): This measures the camera’s side-to-side view, as if you were panning the camera left and right.
- Vertical Angle (V): It gauges the camera’s top-to-bottom perspective, as though you were tilting the camera up and down.
In essence, the lens angle, or FOV, is a practical way to define how much of the world the camera can encompass both horizontally and vertically in its frame.
The spectrum of camera Lens Angles
With thousands of camera manufacturers for all different applications, you can find an almost infinite range of field of view angles. Some personal adventure cameras can record in a full 360 degree coverage. Microscope cameras on the other hand will give you essentially a pinpoint camera angle, close to 0 degrees.
CCTV cameras exist somewhere in between these two extremes. Generally a security camera’s vertical (V) field of view is around half its horizontal (H).
Typically wide angle security cameras have a field of view of around 180 degrees horizontally, and 90 degrees or less vertically. For example, this Dahua Wide Angle Dome Camera has a horizontal FOV of 180 degrees, and a vertical FOV of 78 degrees for one configuration.
Longer focal length cameras with narrower angles obviously give a much tighter field of view. For example, this Dahua Bullet Camera provides a long focal length of 8mm compared to its shortest configuration of 3.6mm. In this long focal length, the horizontal FOV is only 43 degrees, whereas the vertical drops to 24 degrees.
The spectrum of angles is not black and white, and there exists a solution for almost any problem. Using the bullet camera mentioned in the narrow angle, its shorter focal length configurations give a wider FOV that is still not as large as the wide angle.
In its shortest configuration, you can expect a horizontal FOV of 92 degrees, and a vertical of 45 degrees. This is around two times wider in both directions than its narrow setup, but still a long way to go to the wide angle dome camera mentioned previously.
Technically a subset of narrow angle cameras, we feel telescope cameras deserve their own mention. For some specific applications you may need to cover a very small field of view with great detail. Perhaps your target scene is very far away and bringing a camera closer is not feasible.
Trade off between Camera Angle and Image Detail
You may think, since wide angle cameras capture a larger field of view, why not use them everywhere? Why use narrow angle cameras at all? These are good questions, and the answer is: Detail.
Cameras are made with a certain video resolution which determines how much detail you can see in the footage. A higher resolution means more details in your picture. With a wider angle camera, this resolution has to be stretched over a wider field of view.
Ultimately this means less pixels per angular degree, or less pixels per feature. For example a narrow angle camera may capture a whole facial photo at a certain distance, whereas a wide angle might only get a rough idea at the same distance. In the diagram below, you can see that although the narrow angle covers a smaller angle, it captures that area in much finer detail.
- Wide Angle = bigger picture, blurrier details
- Narrow Angle = smaller picture, finer details
How to choose the right angle for your needs?
If you’ve made it this far, you are now armed with a treasure chest of technical considerations about camera lens angle. The real reason you are reading this article is most likely to decide which cameras to use for your property security – whether residential or commercial.
Once you understand the fundamentals, it is quite simple to choose. A wider area to cover needs a wide angle camera, or if you have unlimited budget you can cover it with multiple narrow angle cameras. A narrow area can do with a narrow angle camera.
Some quick examples:
- Parking lot – wide angle camera
- Hallway – narrow angle
- Shopping isles – narrow angle
- Cash registers – narrow angle (or wide angle if you have a lot)
In conclusion, the lens angle, or the field of view, of a CCTV camera is vital to its functionality and performance as a security element. A narrower angle will mean a smaller field of view, but higher details for the same area. A wider angle will mean a broad area covered, but with less details.
For tighter spaces, you should probably use narrow angle cameras, and for wider areas go for a wider field of view. If you are having trouble deciding, or want a second opinion, feel free to get in touch with us for a consultation.