What are the effects of focal length, aperture, and pixels on home video cameras?

Aperture: F1.0/F1.2/F1.6/F2.0……

Focal length: 2.8mm/3.6mm/6mm...

Pixel: 200W/400W

Resolution: 1080P/2.5k/4k...

For general network cameras, the marked parameters include focal length, aperture, pixels, resolution, etc. When choosing a home network camera, how to choose and what do these parameters represent? Let me give a detailed answer to the above parameters

1. Aperture

The aperture of a camera is actually the same concept as the aperture of a camera or a mobile phone. First, the light from an object enters the camera through the lens and forms an image on the photosensitive element. Only then can we see the images captured by the camera. The function of the aperture is to determine the amount of light entering the lens, just like the width of a water pipe, the larger the aperture, the greater the amount of light entering. For the size of the aperture, the F/number is used. The value after F is opposite to the aperture size, that is, the smaller the number, the larger the aperture and the more light entering.

For users who need more night shooting, you can consider choosing a camera with a large aperture (small value) and infrared night vision function. For home cameras, an aperture of F2.0 can meet the needs of outdoor monitoring and provide clear shooting pictures.

Note: The smaller the aperture, the darker the image, and the better the depth of field; the larger the aperture, the brighter the image, and the worse the depth of field; so now black light cameras, why improve the imaging effect at night, use lenses with apertures such as F/0.9 or F/1.0 , but the image focus stroke is short, it is easy to be out of focus, and the image is not clear, and the ordinary network camera generally uses F/2.0 or F/1.8 lens, the image focus stroke is long, and the image is clear, so it is not a light image Bigger is better, it's both.

2. Focal length

The focal length is the distance from the focal point to the center point of the mirror.

　　镜头焦距越小，看到的东西越小，画面范围更广;镜头焦距越大，看到的东西越大，画面范围更窄。

3.6mm focal length

6mm焦距

● 3.6mm focal length: 89°horizontal field of view, 108°diagonal. It is possible to shoot a wider position laterally.

● 6mm focal length: 53°horizontal field of view, 60°diagonal. Objects that are farther away will be larger when viewed, and distant objects are recorded more clearly.

Therefore, you can choose a 3.6mm camera if you need to shoot scenes such as the entrance of a house, and a 6mm camera is more suitable for monitoring such as factories and parking lots.

3. Pixels, resolution

Although both pixels and resolution are directly related to the clarity of shooting, the two are actually different concepts. A picture is composed of pixels, and a pixel is the unit of resolution.

1080P(1920*1080), 2.5K(2560*1440), 4K(3860*2140) refers to the resolution, that is, the number of pixels in the picture in the two dimensions of length and width, and the product is the total pixels, which is our We often say 200W and 400W pixels.

Generally speaking, the more pixels, the higher the resolution and the clearer the picture.

But is the higher the resolution of the camera, the better? This should also be selected in light of the actual situation.

Because a higher resolution will have more pixels when recording the same picture, and the data size generated during transmission will be larger, which will take up more storage space and generate additional traffic. If the WIFI signal is not good , or a 4G camera, the higher the pixel, the more bandwidth it takes up, and it will freeze. According to the actual monitoring needs, in some indoor and outdoor scenes with good light, 2.5K is enough for use, and there is no need to deliberately Go for high resolution.