|High Definition Video Recording:||1080p|
|Video recording speed, up to:||30 frames / sec|
|Auto focus:||there is|
|Installation type (mount):||universal|
|Features:||Autofocus. Tripod capability|
Can you see / hear me? How in work?
It should be noted that the goals of acquiring a webcam can be very different. video recording, streaming and broadcasting, participation in stakes / webinars, group calls with friends in the era of general quarantine, and so on. And this product successfully copes with all of the above and even more.
The device is very user-friendly in use, the connection does not require the installation of additional specific programs or drivers, we connect to a computer / laptop / MacBook and you’re done.
Having placed the webcam on a laptop monitor, we pleasantly find that it is compact and visually does not take up much space at all. The 1.5m USB cable allows the device to be placed at a relatively large distance from the connection port.
Image transmission was tested in the currently popular program Zoom. The internal settings of the application allowed us to evaluate various features. blurring the background, mirror image rotation, hiding facial skin imperfections, etc. What I would like to say about the picture. the image is clear, the image quality corresponds to the declared one, the device conveys color saturation and contrast well.
Auto-focus is triggered when the object is at a distance of 10 cm from the webcam.This allows you to show colleagues or friends any necessary information online, highlighting key points.
The device adjusts well to the light level. the manufacturer has declared decent image quality in low light conditions. We looked at how the camera works in minimal lighting in the room, leaving only the floor lamp on in the room. The result exceeded expectations. the image did not lose clarity and contrast, no noise or interference was detected during transmission. This is a clear advantage because in winter, it is rather cloudy outside the window and it gets dark early, while we do not always turn on full lighting during the day.
The built-in digital microphone has good sensitivity, reduces extraneous noise (for example, the sound of pressing the keyboard or footsteps around the room), the transmission of voice sound is heard well and clearly. Of course, the built-in microphone will not replace a full-fledged device in terms of sound volume (as a separate device or as part of a stereo headset), but it is quite suitable for negotiations on online calls or web conferences.
We also checked that the device can be mounted on a tripod. adjustable height of placement, as well as a good length of the cable allows you to provide the necessary location of the webcam in space and stream / conference from the desired point of view.
Who is it for?
Webcam A4 PK-930HA is a compact, stylish and up-to-date product that will serve as a small and good gift for a colleague, streamer, gamer or just a lover of Internet communication.
In addition to transferring data in high quality resolution, a nice feature of the camera that distinguishes it from other models of this series is the presence of autofocus, which will save you from the need for manual adjustment.
How To IMPROVE Your Webcam Quality: ULTIMATE GUIDE
On the Yandex.Market site. This product justifies the price and pays for the investment with interest. Webcam A4 PK-930HA will become your reliable companion and assistant in the field of online meetings and important negotiations.
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Another important aspect is the shooting resolution. You should be aware that webcams can take photos and videos with different resolutions: for a photo it will be larger, for a video it will be less. You should focus on video resolution.
As a rule, for work tasks, for example, to communicate with students on Skype, video resolution from 1280 x 720 to 1920 × 1080 (HD) will be sufficient. If you shoot videos for YouTube, you can pay attention to more expensive webcams with FullHD-resolution (1920 × 1080 and higher).
CHIP recommends: HD cameras
As a rule, the webcam is connected to the computer via a USB 2.0 connector, the latest models. via USB 3.0. There are also models with Wi-Fi support. they are usually professional and are designed for office video conferencing.
When a camera is connected, it is automatically detected by the system, and a driver is selected for it. Therefore, pay attention to which OS support is declared for this camera: Windows, MacOS, Linux. Of course, the drivers can be installed from the included disk, or downloaded from the manufacturer’s website.
CHIP recommends: USB 3.0 webcams
Viewing angle and rotation
The angle of view of the camera lens determines how much space will fall into the frame. just your face, your surroundings, the whole room. Modern webcams have a viewing angle ranging from 45 ° to 170 °. Golden mean. somewhere 60 °.
The camera can be panned horizontally to give more view, and tilted left and right to give different angles. For different cameras, the horizontal rotation angle can be up to 360 °, tilt. up to 180 °.
Certain camera models can follow your face and automatically turn in the right direction so that it is always visible due to the mechanical drive.
CHIP recommends: face tracking webcams
Computers have eyes: how to choose a webcam?
A good webcam is an important tool for those who regularly use video communication: distance teachers, streamers, video bloggers. Therefore, the main aspects of choosing a webcam relate to how high-quality picture it is capable of giving. The Matrix The first aspect is, of course, the matrix. There are two types of webcam matrices: CCD and CMOS. The first type is deprecated and should be avoided, although it is already practically [. ]
A good webcam is an important tool for those who regularly use video communication: distance teachers, streamers, video bloggers. Therefore, the main aspects of choosing a webcam relate to how high-quality picture it is capable of giving.
The first aspect is, of course, the matrix. There are two types of webcam matrices: CCD and CMOS. The first type is obsolete and should be avoided, although it is almost never found anymore. with rare exceptions, for example, for parental control cameras built into children’s toys.
Modern webcams are available with a CMOS matrix from 0.1 to 5 megapixels. Here, of course, the bigger is better rule. A clear picture, sufficient for shooting videos, is provided by webcams from 2 MPix. be guided by this figure.
CHIP recommends: 2 MPix cameras
A number of options make the webcam more convenient to use:
- Built-in microphone eliminates the need for a separate external microphone or headset.
- Digital zoom makes it possible to enlarge the picture several times without losing clarity.
- Manual focus allows you to independently adjust the focus of the camera to get the perfect picture.
- The curtain is an indispensable thing for those who are convinced that they can be monitored via a webcam. 🙂 It covers the lens when the camera is not in use.
- Backlight is another handy feature that allows you to shoot in the dark.
CHIP recommends: webcams with built-in microphone
Logitech Web camera: Zoom or Get closer to your webcam
about the choice of video equipment:
The clarity of the image, or the resolution of surveillance cameras is the ability of the device to confidently record the minimum dimensions of the surveillance object at a certain distance from the camera.
The resolution, and accordingly, the clarity of the image depends on:
- on the quality of the lens and its focal length;
- on the technical characteristics of the CCD (the number and quality of pixels);
- from distance: “lens. observed object”;
If a visual receiving device (monitor) is used, then the following are added:
- the quality of signal conversion in the receiving device (video recorder);
- technical characteristics of the reproducing device (monitor);
For different cameras. analog and IT-technologies (digital) clarity is determined by its characteristics.
The angle of view of the CCTV camera and its calculation formula
A video camera is a mechanical device consisting of a body, a lens and an electronic converter of an optical image into an electronic form of signals:
- The body is the main power element designed for fastening various parts of one product.
- Lens. an optical element consisting of one or more lenses with different diopters. Responsible for creating a virtual or real image in an enlarged or reduced form.
- An electronic converter, or, in other words, a CCD matrix is an integrated microcircuit consisting of photodiodes that convert a light signal (image) into a set of electrical signals for the purpose of their further transmission to a receiver (monitor).
Calculation can be performed using several methods.
The angle of view directly depends on the focal length. It follows that, having calculated the latter, by means of the above table 1, it is possible to determine the desired angle.
The calculation formula looks like this: f = rA / L, where:
- f. lens focal length.
- r. metric distance to the object, measured in meters.
- A is the size in millimeters of one of the sides of the matrix; the one that defines the observation plane is accepted: vertical or horizontal observation area.
- L. object dimensions in meters; taken in accordance with the dimensional side of the matrix: vertically or horizontally.
In this case, the final formula takes the form: f = rA / (100L / h), where:
- h. full size of the object on the screen, expressed as a percentage;
Manual calculations using this technique are quite time consuming, therefore, appropriate programs for computer calculations were developed.
The object of observation is the entrance gate to the territory of the enterprise. The task facing the surveillance service is to record the stamps and license plates of entering and leaving vehicles.
Initial data for the calculation:
- r = 10 meters. distance from the lens to the border of the gate;
- h = 5%. horizontal size of the object on the monitor;
- A = 8.46 mm (1/3 “), is the size of the matrix;
- L = 0.52 meters. the size of the license plate;
Then the focal length of the lens will be: f = 108.46 / (1000.52 / 5) = 10.429 mm.
Checking the table, we see that the camera’s angle of view will be about 27 degrees.
The angle of view can be determined in a shorter way, but Honor needs that inexpensive lenses suffer from optical distortion, especially strong spherical aberration.
Calculation formula: a = 2arctg (b / 2f), where:
- a. angle of view of the video camera, in metric degrees;
- trigonometric function (arctangent);
- b is the size of the matrix in millimeters on one of the sides;
- f is the effective focal length of the lens in millimeters;
The object of observation is exactly the same as in the above example. We accept the initial data exactly the same.
The viewing angle will be: a = 2arctg (8.46 / 210.5) = 29 degrees.
The discrepancy between the results is caused by a slight rounding of the original data to the second decimal place.
The viewing angle characterizes the apparent girth of the observed space. Directly depends on the focal length of the lens and the size of the CCD-matrix. So, with the same lenses, the viewing angle will be larger for a video camera with a larger matrix.
In any optical-mechanical device, including in a surveillance camera, there are a number of important characteristics by which the efficiency of their work is determined:
- Focus and light sensitivity of the lens;
- CCD matrix format;
- the possibility of digital signal processing;
- angle of view of the video camera;
All these characteristics are closely interconnected and determine, in fact, the power of the optical instrument.
Let’s consider one of the most important indicators. the viewing angle of a video camera. To make it clearer what it is, you can draw an analogy with a human optical instrument, the eye is the angle of view, the coverage of the maximum visible space.
Analog video cameras
For this type of cameras, the TVL indicator is used. television lines. Shows how many alternating black and white lines are placed on the measured area in the vertical or horizontal planes.
Analog cameras, according to the degree of resolution, are subdivided into devices:
- with an average image quality: about 500 pixels. corresponds to 380. 420 TVL;
- high degree of resolution: over 750 pixels. over 1000 TVL, respectively;
Many are familiar with this characteristic. this is how the properties of a video camera in a mobile phone are characterized.
Figure 1 (at the beginning of the article) shows that objects “1” and “2”, located at the same viewing angle, are displayed on the matrix in the same way, the number of pixels involved per perception of both objects is equal. In other words, the amount of information comes in different, but the closer located object has a smaller amount of data. its detailing is clearer, small details are not “smeared”, do not merge with each other.
In order to increase the resolution and detail of the object, it is necessary to bring the object “2” closer to the lens. This is done by changing the focal length, that is, the camera “zooms in” to the object. But this is applicable only for camcorders with lenses with variable focal length (“floating” lens).
It is possible to equip the receiving device with special software that allows processing the received digital signal in order to increase the detail of the observed object. But this will lead to a significant increase in the cost of the video surveillance system.
Examples of the dependence of the clarity of the picture on the focal length of the lens, angle of view and distance to the object are given in the table:
|Lens focal length, mm||Horizontal angle of view for matrix = 1/3 ”, linear degrees||The ability to detect a person, meters (approximate data)||The ability to identify a person, meters (approximate data)||The ability to determine the car number, meters (approximate data)|
When calculating distances, European standards are taken as a basis:
- 20 pixels / meter is the norm for resolution when an object is detected in the field of view;
- 100 pixels / meter is an indicator used for object recognition;
- 250 pixels / meter. identification resolution;
The text contains the determining factors responsible for the angle of view of the camcorder.
But during operation, such factors arise that affect the performance of the device:
- impairment of the lens performance, in the case of the manufacture of the optical component from a polymer material (lens clouding);
- poor-quality fastening of the body to the supporting structure (tremor from gusts of wind or other influences);
- loss of its properties as a lubricating component in the construction of a video camera (the complexity of moving the camera itself or the lens);
- electronic interference affecting the transmitted signal, as well as various other factors;
In addition to theoretical calculations for the viewing angle, important factors are:
- the installation point should provide maximum visibility in the vertical and horizontal planes;
- protection from the effects of climatic or any mechanical influences;
- availability, when performing preventive work on adjusting the video camera and preventive maintenance;
Each object requires an individual approach when determining the viewing angle, the clarity of the picture on the monitor. All this is determined when setting tasks to determine the parameters of the observed territory and is calculated by specialists.