What is the angle of view in CCTV cameras?
Security cameras. this is primarily your safety, and it is NOT desirable to save on it. And this applies not only to the financial part. DO NOT save time getting the necessary knowledge to select a camera. The choice is influenced by many parameters, the quality of image transmission, detail, what kind of view in CCTV cameras. over, the last parameters are one of the decisive.
What is the viewing angle?
Each CCTV camera has its own viewing angle, it shows how much of the territory will be covered. This very angle of view depends on the size of the matrix and the focal length of the camera. These two parameters are interrelated. There is a table showing this very relationship. For a 6mm CCTV camera, the angle you need will be marked in the table. For example, the horizontal field of view with a 6mm focal length is about 33 degrees. It should be noted that in the table, basically all data are given for a camera in a horizontal position. To obtain data in the vertical plane, take into account the ratio of the horizontal and vertical sides of the matrix, which is 16: 9.
How to determine the quality and angle of view of CCTV cameras?
To determine the quality, you can use several options. Simplest. ask the seller, but he himself may or may not have reliable information. As they say: trust, but verify. Check it yourself using the table of the dependence of the focal length on the viewing angles. It contains the following items:
- Focal length;
- Viewing angles (horizontal, vertical and diagonal)
- Recognition distances and best quality.
You can find out the focal length on your own, and from this you can already push off to clarify the viewing angle. To do this, you need to learn how to calculate the angle of view of a CCTV camera, for this you need to perform several mathematical actions.
F. lens focal length (mm)
R. distance to the object (m);
A. die side size (horizontal or vertical) (mm)
L. object size measured in (m).
The formula by which you will calculate this. F = RA / L.
The indicator we get will show the object in full screen. Adjust the value so that the object occupies only part of the screen. To do this, you need to make some adjustments to the formula. Will add the h value to it. This will be the size of the object, the reading on the screen, as a percentage. The shape will look like this: L: L ‘= 100L / h.
Finally, we get the following formula: f = RA / L ‘. Note that the largest angle of view will be in cameras with a large camera format and no more, but even a small focal length. When the focal length becomes larger, then the matrix format. smaller and the viewing angle is correspondingly reduced.
Choosing a camera with the right viewing angle
How to choose the angle of view of a CCTV camera. One of the popular questions. First you need to determine where the camera will be used. CCTV in a long and narrow corridor does NOT need a wide angle camera. True, they perfectly realize themselves in widescreen image transmission, in panoramic shooting.
Wide angle cameras with a viewing angle over 100 degrees are poor in detail. An example of this is a person’s face, you will NOT be able to see it already from a distance of 5 meters. A small viewing angle will allow you to accurately recognize the details that wide-angle cameras are NOT capable of. Range. 20-50 meters. The average viewing angle is equal to the viewing angle of our eye. Range. 10 meters. To combine two factors: wide format and detail. you need to install a movable camera.
Viewing angle 120 °. Or real viewing angles of CCTV cameras
and more often our clients ask for CCTV cameras with a viewing angle of 120 degrees or more. Most people who are not familiar with this topic are sure that this is a typical value for standard video cameras. To be honest, many of the sellers also claim that cameras with a 2.8 mm lens have a 120 ° horizontal field of view. Let’s take a look at the real values. We have already measured the real angles of car DVRs, and debunked the myth that most of them have a viewing angle of 120 degrees or more.
When choosing equipment for a security surveillance system, of course, it is important to take into account the viewing angle of CCTV cameras, on which the size of the observed area depends. Its value is influenced by 2 parameters. The focal length of the lens and the diagonal of the matrix, with an increase in which the angle of view will expand. But as the angle of the field of view increases, the image detail decreases. detail requires higher resolution or a camera with a finer angle of view.
For a visual comparison of the angles of the field of view on cameras with different lenses, an experiment was carried out, which is described later in the article.
We used 4 IP cameras with different lenses:
- 3.6mm. PN-IP2-B3.6 v.2.6.3
- 2.8mm. ST-181 IP HOME
- 1.9mm. PNL-IP2-B1.9MPA v.5.5.2
- 1.4mm. PDL-IP2-B1.4MPA v.5.8.9
The tested camcorders differ in the focal length of the lens. Cameras with 3.6 and 1.9mm lenses have the same matrix size 1 / 2.9 inches, cameras with 2.8 lens have a slightly larger matrix. 1 / 2.7 “. And the resolution of all cameras is 2 Mp.
All video cameras were placed at a height of about 2 meters opposite the “test” wall in our office. The camera views are centered to better assess the difference in the width of the field of view. One photograph was taken for each of the following three cameras:
Viewing angle of a camcorder with a 3.6mm lens:
PN-IP2-B3.6 v.2.6.3 with a focal length of 3.6 mm. The 2 outermost chairs of the managers and part of the right wall are visible. Angle of view is approximately 73 °.
Video camera viewing angle with 2.8mm lens:
ST-181 IP HOME with a focal length of 2.8 mm. Now in the frame you can see about 2 m more. Part of the right showcase and the window on the left. With this camcorder, the angle of view increased to 89 °.
Video camera viewing angle with 1.9mm lens:
PNL-IP2-B1.9MPA v.5.5.2 with a focal length of 1.9 mm. The screenshot shows that both showcases and even a part of the doorway of the trading floor are already captured by this camera. Its viewing angle reaches 109 °.
Video camera viewing angle with 1.4mm lens:
Camcorders with a small field of view have a higher pixel density, which means better image detail. Such a viewing width will be enough for many, so such cameras remain popular in video surveillance. If you need to capture a larger area for observation, a camera with a wider viewing angle is required.
TOP-7. Best webcams of 2020 Final rating!
Greetings to all! My new review is about the best webcams. These tiny devices are indispensable for making video calls and video conferencing. Here are the seven best webcam models to date. All of them are wired and connect to a computer or laptop via a USB port. All Models Described Are equipped with a universal mount-stand, so that each of THESE cameras can be conveniently mounted on a monitor or placed on a table. Moving on to a roundup of the best webcams.
Logitech C270
- Video recording 720p @ 30fps
- 1.3MP standard resolution, 1280 × 720
- Interpolated photo resolution 3 MP, 2048 × 1536
- Viewing angle 60 °
- Constant focus
- Vid HD software support
- Face tracking function when moving in the frame
- RightLight and Fluid Crystal Technologies
- Built-in monaural microphone with RightSound technology
- Compatible with Windows 7/8/10 and above, Chrome OS, macOS 10.10 and above, Android 5.0 and above
- Cable length 1.5 m
The base model Logitech C270 opens the TOP of webcams. This handy, compact device is a simple solution for HD video calling. The webcam is equipped with a standard CMOS lens with a fixed focus and 60-degree field of view for a wide-angle image. The usual camera resolution is 1.3 megapixels. Software processing in interpolation mode allows you to increase the resolution of images up to three megapixels.
The device conducts video broadcasting in a resolution of 1280 by 720 pixels with a frequency of 30 frames per second. The transmitted image is clear, contrasting, bright and colorful. over, regardless of whether shooting is carried out in daylight or in the twilight. RightLight technology is responsible for the sensor’s ability to quickly adapt to lack of light and automatically correct illumination. Thanks to this, and also Fluid Crystal technology, the photos and videos taken by the camera are clear and rich in color. A high-quality picture with good color reproduction is obtained even when shooting in low light conditions. Movements appear smooth and natural.
You also have to worry about good Audibility. The device is equipped with a built-in monaural microphone with RightSound technology, which is responsible for high-quality noise reduction and enhancement of voice sound. Thanks to this, the interlocutor will hear your voice loudly and clearly, even if it is noisy around you.
The webcam is compatible with all common operating systems and supports Skype, Google Hangouts and FaceTime for Mac.
Logitech C310
- Video recording 720p @ 30fps
- 1.3MP standard resolution, 1280 × 720
- Interpolated photo resolution 5 MP, 2560 × 2048
- Viewing angle 60 °
- Constant focus
- Vid HD software support
- Face tracking function when moving in the frame
- RightLight and Fluid Crystal Technologies
- Built-in monaural microphone with RightSound technology
- Compatible with Windows 7/8/10 and above, Chrome OS, macOS 10.10 and above, Android 5.0 and above
- Cable length 1.5 m
The next place in the top webcams belongs to the Logitech C310 model. In fact, this device is an improved version of the previously mentioned Logitech C270 webcam. A key advantage of the C310 is the ability to increase image resolution up to five megapixels by software image interpolation. Other characteristics of these two budget Logitech webcams are identical.
A4tech PK-910H
- Video shooting 1080p, 720p @ 30fps
- Standard resolution 2MP, 1920 × 1080
- Interpolated photo resolution 16 MP 4608 × 3456
- Viewing angle 60 °
- Autofocus
- Swivel mechanism
- Anti-glare coating
- Built-in noise canceling microphone
- Compatible with Windows 2000 / XP / 2003 / Vista / 7/10
- Cable length 1.5 m
The A4tech PK-910H model continues the rating of the best webcams. Designed to resemble an outdoor surveillance camera, this compact device is equipped with a 2 megapixel CMOS sensor with autofocus. The lens has a high-quality anti-reflective coating, which ensures that there are no overexposed areas in the frame, even when shooting in direct sunlight. Automatic image adjustment with intelligent filtering ensures that the picture is clear and the color is correct, even when shooting in low light conditions. Movements are displayed smoothly and naturally.
The webcam captures video in Full HD with a resolution of 1920 x 1080 pixels. The maximum possible shooting frequency is 30 frames per second. The built-in microphone with noise canceling technology delivers high-quality sound. The interlocutor will hear your speech clearly and legibly. As for taking photos, the interpolation mode allows you to increase the resolution of images from two megapixels to 16.
In addition to the universal mount, the camera is equipped with an articulated leg, allowing the device to be rotated 360 degrees horizontally and 60 degrees vertically. The model is compatible with the Windows operating system of various versions.
Microsoft LifeCam HD-3000
- Video recording 720p @ 30fps, 16: 9
- Resolution 1.3 MP, 1280 × 720
- Viewing angle 68 °
- 4x digital zoom
- Autofocus
- Face tracking function when moving in the frame
- Support for special effects (face masks, wigs, etc.)
- TrueColor technology
- Built-in noise canceling microphone
- Compatible with Windows 8 / 8.1 / 10
- Cable length 1.8 m
The next position of the TOP is taken by the Microsoft LifeCam HD-3000 webcam, which provides high-definition video communication in HD format. This device records video in 16 by 9 widescreen cinema format and 1280 by 720 pixels at 30 frames per second. The camera is equipped with a 1.3 megapixel sensor, CMOS sensor, auto focus and 4x digital zoom. TrueColor technology provides automatic exposure control for bright colors, even in low light conditions. Built-in omnidirectional noise canceling microphone delivers crystal clear sound.
The webcam is equipped with a universal-type stand-mount with a bendable leg, which can be shaped into almost any shape for the most convenient fixation of the device. The camera is certified for Skype and Microsoft Lynk, and supports fast video sharing via messaging services. Youtube or. Full functionality is available on devices running Windows versions 8, 8.1 and 10. For Windows 7 and Mac OS, camera functionality is limited.
Logitech C922
- Video capture 1080p @ 30fps, 720p @ 60fps
- Resolution 2 MP, 1920 × 1080
- Glass lenses
- Viewing angle 78 °
- Autofocus
- Capture software
- Personify background replacement function
- Support for mounting on a tripod
- Built-in stereo microphone
- Compatible with Windows 7/8/10 and above, Chrome OS, macOS 10.10 and above, Android 5.0 and above
- Cable length 1.5 m
Another webcam from Logitech that should be mentioned among the best is the C922. This cool device is geared towards streamers. The powerful camera is designed for live streaming on Twitch or Youtube channels. It streams ultra-high-speed HD video at 1280 by 720 pixels at 60 frames per second, and Full HD video at 1920 by 1080 pixels. at 30 frames per second.
The webcam is equipped with a 2-megapixel lens with glass lenses, CMOS sensor, high-quality autofocus and a wide viewing angle of 78 degrees. There are no complaints about the quality of the transmitted picture. the palette is bright, the color reproduction is accurate and natural, the detail is excellent. The video streaming is smooth, without jerks and delays. Auto Light Level Correction keeps the image clear and detailed even when shooting in dim light.
The device picks up sound from anywhere in the room. This is answered by two omnidirectional microphones mounted on both sides of the lens. Thanks to them, the voice will sound clear and natural in the broadcast video. The camera is compatible with most operating systems and supports XSplit Broadcaster and Open Broadcasting Software.
Microsoft LifeCam Studio
- Video shooting 1080p, 720p @ 30fps
- Standard resolution 2MP, 1920 × 1080
- Photo resolution up to 8 MP
- Glass optics
- Viewing angle 75 °
- 3x digital zoom
- Autofocus from 10 cm
- Swivel mechanism
- Face tracking function when moving in the frame
- Support for special effects (face masks, wigs, etc.)
- Technologies TrueColor, ClearFrame
- Support for mounting on a tripod
- Built-in noise canceling microphone
- Compatible with Windows 8 / 8.1 / 10
Next in the top is the Microsoft LifeCam Studio webcam. another model in this rating that visually resembles an outdoor surveillance camera. This device is perfect for both streaming and simple Skype communication.
The camera is equipped with a 2-megapixel Full HD CMOS sensor with a wide viewing angle and autofocus from 10 centimeters to infinity. The 1080p high resolution sensor ensures excellent image quality. The picture is crisp, detailed, bright and multicolored in almost any environment. This is ensured by high quality glass optics and TrueColor technology. ClearFrame technology, in turn, provides smooth video streaming, without jerking. Full-range built-in microphone delivers clear and realistic sound.
The camera mount is designed with a special hinge that allows the device to be half-rotated in both directions for a full 360-degree view.
Logitech BRIO
- Video recording 2160p @ 30fps, 1080p @ 30 / 60fps, 720p @ 30/60 / 90fps
- 8MP standard resolution, 4096 × 2160
- Glass lens
- Adjustable viewing angle 65/78/90 °
- 5x digital zoom
- Autofocus
- HDR
- RightLight Technology
- Face tracking function when moving in the frame
- Windows Hello facial recognition
- Personify background replacement function
- Protective shutter
- Support for mounting on a tripod
- Built-in stereo microphone with noise canceling
- Compatible with Windows 7 / 8.1 / 10 and above, Chrome OS 29.0.1547.70 and above, macOS 10.10 and above
- Cable length 2.2 m
The Logitech BRIO model completes the TOP of webcams. This device fully deserves the “super” prefix. It belongs to professional-grade webcams and is focused on large-scale streaming activities. From the manufacturer, it has received the proud title of the most high-tech webcam in the world. The camera is capable of shooting in resolutions up to 4K and at high frame rates.
Equipped with RightLight and Wide Dynamic Range, or HDR, for stunning night photography. Also worth noting is the 5x digital zoom. The camera settings anticipate the adjustment of the lens’s field of view. 65, 78 and 90 degrees are available for selection. The 8-megapixel sensor performs well even when shooting in twilight conditions. In any light, the transmitted picture is distinguished by bright colors and accurate reproduction of details, without distortion and blurring. High-quality sound is provided by two built-in omnidirectional microphones with noise canceling.
The camera supports Windows Hello facial recognition. Optical and infrared sensors, which the camera is equipped with, respond to its error-free operation. This feature allows you to log into your account without entering a password. The device supports work with almost all video communication services.
On this, the rating of the best webcams has come to an end. Bye everyone!
CCTV camera focal length
The focal length of a CCTV camera lens is a video camera parameter that we take as a basis for calculating the surveillance area. Here its value and the physical size of the matrix depends on the angle of view of the lens. Having carried out non-complex geometric calculations, you can quite accurately determine the area that will fall into the frame of the CCTV camera.
For video surveillance over large areas, cameras with a wide viewing angle are used. And when viewing objects “clamped”. Like a long corridor with a thin.
Parameters affecting the viewing angle
As mentioned above, the three parameters of the video camera are interdependent, these are:
- Lens focal length;
- Lens viewing angle;
- The physical size of the video camera matrix.
The longer the focal length of the lens, the smaller the angle of view. Therefore, you can observe objects that are located at a great distance from CCTV cameras. Conversely, the shorter the focal length, the larger the angle of view. Accordingly, more objects fall into the camera frame.
The viewing angle also depends on the size of the sensor array. The larger the matrix, the smaller the camera angle of view and vice versa.
Calculating the focal length of a camcorder lens
Calculation of the focal length of a CCTV camera is necessary for the correct selection of a video camera. Of course, manufacturers indicate the physical size of the matrix, the focal length and sometimes the angle of view in the technical specifications. But for a general understanding, let’s see what affects the choice of focal length, these are:
- At what distance is the object of observation;
- The physical size of the matrix;
- Object size.
So, having the given technical characteristics of the camera, you can calculate the focal length of the CCTV camera lens using the following formulas:
F = hS / H or F = vS / V,
Where h. horizontal size of the matrix;
S. distance to the object of video surveillance;
H. horizontal size of the object;
V. vertical size of the matrix;
V. vertical dimension of the object.
The dimensions of the sides of the CCTV camera matrix are given in the table:
| Matrix size | 1/4 ” | 1/3 ” | 1/2 ” |
| Horizontal, mm | 3.2 | 4.8 | 6.4 |
| Vertical, mm | 2.4 | 3.6 | 4.8 |
An example of calculating the focal length and choosing a camera
It is necessary to observe the entrance and passage through the gates to the territory of the enterprise;
Objective of surveillance: detection of cars and people at the entrance to the territory of the enterprise;
The width of the passage and the gate is 6 meters;
The distance from the camera to the passage is 7 meters;
Camera Proto AHD-1W-EH10F (?) IR, after the letter F the focal length should be indicated. We will calculate it according to the above formula:
Where 3.2 is the vertical size of the matrix, because. In the Proto AHD-1W-EH10F (?) IR camera, a 1/4 “matrix is installed. Since the lenses on the camcorder are made with a fixed focal length, we select the closest smaller T. K. If you select the nearest larger one, then part of the object is not will fall into the camera frame.
Let’s perform another test of the camera for suitability. The control zone is 6 meters wide, the task is to detect. When a person is detected, it is necessary that for one meter of control there are 20-30 pixels of camera resolution. With simple calculations, it can be seen that the Proto AHD-1W-EH10F36IR camera is capable of not only detecting, but also recognizing a person on an object, it does not speak about cars. In fact, it is still necessary to calculate the vertical focal length, as well as the height and angle of installation of the video camera, but we deliberately omit these calculations, since K. We do not set ourselves the task of a complete calculation, we wanted to show in this example only the method for calculating the focal length and choosing a camera for this calculation.
Matrix format 1/4 “. Matrix format 1/3”. Matrix format 1 / 2.5 “
To calculate the basic parameters of CCTV cameras, you can use a free calculator, with which you can not only get the numerical values of indicators, but also visually determine how a group of silhouettes of people in the frame will look like. You can download the calculator here.
Situations often arise when it is not possible to clearly define the control zone by a video camera, or it becomes necessary to change the size of this zone, but with a small frequency. It also happens that a person wants to more accurately determine the control zone on the spot. In THESE cases, a camera with a varifocal lens will help, where you can manually change the focal length without any problems. If you have a need to zoom in or give an object quickly, you can use a camera with a motorized lens. There are cameras that allow you not only to quickly change the focal length (zoom in, zoom out the object), but also change the angle of video surveillance within 360 degrees horizontally and 180 degrees vertically. Such cameras are called Speed doome, you can read about them in the article “Speed dome cameras”
There are cameras with a corridor video surveillance mode. Such a camera is installed vertically, and the image is rotated 90 degrees. Thus, the monitor displays the picture not horizontally, but vertically. This reflects more “useful” information than would be the case with a normal camera position.