Number of LEDs
The number of backlight LEDs (see "Design and capabilities") provided in the camera design.
Theoretically, more LEDs provide more power and, accordingly, range (see below) and efficiency
of IR illumination or LED illumination. However, in fact, such light sources can vary markedly in performance; in addition, a lot also depends on the features of the camera itself. Therefore, in fact, this indicator is a reference, and when choosing, it makes sense to pay attention to parameters that are closer to practice — in particular, the same backlight range (see below).
Illumination range
Operating range of the backlight (see "Design and capabilities") installed in the surveillance camera. This term usually means the maximum distance from the camera to the observed object, at which it is able to provide a relatively high-quality and legible image in the complete absence of other light sources. Of course, the actual backlight range may differ from the claimed one, and these differences are most often in the direction of increase (for example, due to the presence of the same additional light sources). However, if the possibility of shooting with backlight is important for you, you should focus on the claimed range.
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.
Material
The main material used in the construction of the camera body.
— Plastic. Inexpensive and at the same time quite practical material. Plastic is light, quite strong (not as strong as metal, but still quite sufficient for most cases), chemically inert (and therefore not susceptible to corrosion and insensitive to moisture), and also has a relatively low thermal conductivity (which provides additional protection for extreme temperature fluctuations). Due to all this, this material is very popular in indoor chambers (see "Usage"). At the same time, it is somewhat less suitable for outdoor work.
— Metal. The main advantage of metal, in comparison with plastic, in the case of surveillance cameras is high strength and reliability. This allows you to use it even for street models that work in difficult conditions and must have a certain anti-vandal resistance (at least not immediately “give up” when trying to break or break). At the same time, such material is much more expensive, and therefore less common.
