Number of megapixels
Camera sensor resolution in megapixels (millions of pixels).
The higher the resolution of the matrix, the higher the video resolution can be (see below), the more detailed the image is capable of providing the camera. At the same time, note that as the number of megapixels increases (without changing the size of the matrix), the size of each individual pixel decreases, which increases the likelihood of noise and deterioration in the overall image quality. Therefore, high resolution in itself is not necessarily a sign of high quality — a lot depends on other things, for example, on the size of the matrix (see above).
As for specific values, in the most modest matrices it does not exceed 1.3 MP, which corresponds to the maximum
HD resolution.
2 MP sensors allow for already Full HD resolution (usually 1920x1080 or 1600x1200),
3 MP,
4 MP,
5 MP and
6 MP are capable of better resolution, but still do not reach
4K, which is typical for 8 MP.
Video resolution
The maximum video resolution that the camera can capture.
The higher the resolution of the video, the more details you can see on it, the less details will be blurry. On the other hand, high resolution means large volumes of video materials, which, accordingly, requires capacious media for their storage and fast communication channels for broadcasting video in real time. Yes, and this indicator significantly affects the cost of the camera.
Aperture
Aperture of the lens installed in the camera.
Aperture characterizes the degree of attenuation of the light flux when passing from the front lens of the lens to the matrix. It is denoted as the ratio of the diameter of the active aperture of the lens to the focal length, while the size of the active aperture is designated as f and is taken as a unit — for example, f / 1.4 or f / 2.0. Moreover, the smaller the number in the designation, the higher the aperture (in our example, the second lens will be darker than the first). And for lenses with a variable focal length (see "Focal"), the actual aperture, usually, changes with a change in focal length; for such models, either the range of aperture values, or its maximum value, can be indicated.
By itself, this parameter characterizes, first of all, how light the image taken through the lens turns out, all other things being equal. High values are important, first of all, when shooting in low light conditions: a fast lens allows you to get a fairly high-quality image without increasing the sensitivity of the matrix, which is fraught with noise and “blurring” of the picture. On the other hand, the actual quality of camera operation (including in dark conditions) also depends on many other factors — the type and size of the matrix, signal processing features, etc. Therefore, aperture in most cases is more of a reference than a practically significant parameter.
Operating temperature
The ambient temperature range in which the camera can be used normally.
All modern surveillance cameras normally tolerate temperatures typical for houses / apartments, offices and other premises with similar mild conditions. Therefore, it is worth paying attention to this parameter, first of all, if the device is planned to be used outdoors — or in a room where the temperature does not differ much from the street temperature or, for technical reasons, should be low (freezer warehouse, refrigerated car, etc. ). In such cases, the lower temperature threshold is especially important: for example, almost all outdoor cameras have the ability to work
in cold temperatures below 0 °, but among indoor models such features are much less common. However,
frost-resistant devices(with an allowable temperature of -40 °C and below) can also be found not only among outdoor cameras, but also among “internal” cameras.
As for the upper temperature limit, it is usually not lower than +40 °C, which is quite enough for using the camera in a temperate climate. In some models, this limit reaches +50 °C and even +60 °C, making them suitable even for hot countries. However, note that we are talking exclusively about use in the shade; the possibility of working under direct sunlight should be clarified separately.
