Comparison Dahua H5A vs Dahua H5B

— LAN. The LAN (Ethernet) interface was originally designed to build wired computer networks. Cameras with such a connector, as a rule, also work as network devices. The advantage of this option over the Wi-Fi described below is a higher actual throughput, over BNC — the ability to connect without additional equipment, directly to a standard network router used for a regular computer network. Of the disadvantages, one can note only the need to pull a wire, but this point is common to all wired connection options. In terms of other features, LAN is the most convenient, due to which it has become widespread in modern surveillance cameras.

— Wi-Fi. Wi-Fi connection was originally a wireless analogue of the LAN described above and was used to connect to computer networks. When working in such networks, this connection is similar to LAN in the sense that it allows the camera to work through a regular router (of course, supporting Wi-Fi). At the same time, Wi-Fi is more convenient due to the absence of wires, but with an abundance of other wireless devices connected to the router, the channel throughput and image quality can significantly deteriorate. Note that recently it has also been possible to use this connection in Direct mode - for direct connection of the camera to another device, for example, connecting the camera to a smartphone (see "Design and capabilities -...P2P"). However, this option is less common.

— BNC. Abbreviation for Bayonet Neill Concelman. A bayonet-type connector, usually used to transmit an analog video signal. Refers to professional video interfaces; special equipment is required to work with such a camera. However, cameras with this type of connector are usually in the lower price range. This is due to the limited connectivity options via BNC — it can only transmit a video signal, which limits the functionality of such cameras compared to models that work via LAN or Wi-Fi (see above).

— Aviation port. It is a round multi-pin connector designed for reliable connection of cameras. Such ports provide a stable connection even in conditions of vibration and high humidity, due to which it is used in car video surveillance systems. Power, video signal and control (for example, for PTZ cameras) can be transmitted through one aviation port, which simplifies installation and reduces the number of required cables.

— 3G / 4G. Connecting to the Internet via 3G / 4G mobile networks; as a rule, this requires installing a SIM card from a mobile operator in the camera. The speed of such networks allows, among other things, to broadcast video in fairly high resolution. So such a connection (of course, if there is coverage) is well suited not only as a backup option in case of Internet outages, but also as the main communication channel if there is no fixed Internet connection at all. A typical example of the second situation is monitoring a country house located “far from civilization”, but in an area with reliable mobile phone reception. In both cases, you can contact the camera via the Internet from anywhere on the planet.

Focal length of the camera lens.

The focal length is such a distance from the lens to the matrix, at which a clear image is obtained on the matrix (when the lens is focused to infinity). The viewing angles of the lens primarily depend on this indicator (see below): the smaller it is, the wider the viewing angles and the smaller the objects in the frame (and vice versa). At the same time, it should be noted that the actual viewing angle is determined not only by the focal length, but also by the size of the matrix (see above). In fact, this means that with different sizes of matrices, lenses with the same focal length will have different working angles. Therefore, only cameras with the same matrix size can be compared with each other according to this indicator. Among CCTV cameras, lenses with a focal length of 2.8 mm, 3.6 mm, 4 mm and 6 mm are considered popular.

In models with a variable focal length (see above), in this case, the range from the minimum to the maximum distance is indicated. Also, using these data, you can derive the optical magnification factor of such a lens: for this, the maximum value must be divided by the maximum (for more details, see below).

The power consumed by CCTV cameras during operation. Knowing the indicator of energy consumption, you can, for example, calculate the battery life of equipment from an uninterruptible power supply or choose a suitable “uninterruptible power supply”. Also, with the support of PoE technology, it is worth considering the power consumption when choosing a PoE switch or PoE adapter.