Comparison Dahua DH-IPC-HDBW1320E-W vs Dahua DH-IPC-HDBW1120E-W

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.

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.

The maximum frame rate in the video captured by the camera.

The higher the frame rate, the clearer the image, the less noticeable blurring when moving in the frame (especially fast). On the other hand, this indicator affects the amount of information recorded during shooting, as well as the cost of the camera itself. Therefore, it makes sense to specifically look for a video surveillance camera with high-speed shooting(45 fps and higher) only if a clear recording of fast moving objects is important to you.

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).

Horizontal viewing angle of the surveillance camera. For models with a variable value, the maximum value is indicated, since it is the width of the image that is important, and when zooming in, the zoom factor is more important than the angle. This paragraph also indicates the general angle of view for models with a circular field of view – in particular, cameras with a fisheye lens (see above)

The wider the viewing angle, the more space the camera captures and at the same time, the smaller the images of individual objects in the frame are obtained. Therefore, when choosing by this parameter, it is worth deciding what is more important – the ability to view a large scene or the visibility of small details in a relatively narrow field of view. Also note that with a wide field of view (100° or more), characteristic distortions can be observed at the edges of the frame, and the wider the angle, the more pronounced they are. This phenomenon can be eliminated by panoramic shooting (see "Design and features"), but this feature, in turn, complicates and increases the cost of the camera.

The video compression format used by the camera.

Compression is used to reduce the file sizes of captured video; different technologies can be used for this — the so-called codecs, their list is given in this paragraph. From a practical point of view, compatibility with external recording and playback devices primarily depends on the supported codecs. If you plan to use a computer as a recorder / player, you can ignore this list: modern PCs and laptops usually support a very extensive list of formats, and in extreme cases, the missing codecs can be installed separately. But if we are talking about specialized registrars, individual players (like home media centers), etc. — codec compatibility should be clarified further. So, if the advanced modern H.265 standard is very widely supported nowadays, then the more specific H.265+, originally created for surveillance systems, is much less common even in specialized equipment.