1. There are two kinds of SLR cameras: autofocus and manual focus. Auto focus can change the mode to auto mode, and the camera will automatically adjust the focal length according to the actual shooting situation. Manual focusing can be achieved by rotating the lens.

2. A camera is a device that uses the principle of optical imaging to form an image and records the image with a negative. This is an optical instrument used for photography. In modern social life, there are many devices that can record images, all of which have the characteristics of cameras, such as medical imaging equipment and astronomical observation equipment.

For more information on how to adjust the focal length of a SLR camera, please visit: See More.

A, monitoring camera debugging focal length method:

1, turn on the automatic electronic shutter function of the camera, and adjust the lens aperture to the maximum with the controller;

2. Aim the camera at an object 30 meters away and adjust the focal length to infinity;

3. Use the controller to adjust the zoom of the lens to push the scene farthest, and adjust the back intercept of the lens to make the scene clearest;

4. Use the controller to adjust the zoom of the lens to zoom in on the scene, and fine-tune the focal length of the lens to make the scene clearest;

5. Repeat steps 4-5 several times until the scene is always clear when the lens is zoomed.

Second, the focal length of the surveillance camera refers to the distance between the lens and the photosensitive element. The magnification of a lens is approximately equal to the ratio of focal length to object distance. In other words, with the increase of the focal length of the surveillance camera, the magnification increases, which can narrow the close-range and make the details of the distant view clearer.

Extended data:

1. The monitoring camera shall select the focal length of the fixed-focus lens according to the distance from the monitoring camera to the monitored target. From the focal length, there are short focal length wide-angle lens, medium focal length standard lens and long focal length far lens.

The focal length of a lens is usually represented by f, and the aperture of a lens is generally represented by f, and the value of f is measured by the ratio of the focal length of the lens to the aperture d of light, F=f/d, and each lens is marked with its maximum f value.

2. The best focal length for shooting people is 85mm. According to the standard of 35mm, the focal length of a shot is basically 85mm. The portrait taken with a focal length of 85mm is basically close to the picture taken by a medium format camera, which not only has a suitable sense of distance, but also the face of the person looks natural, and the distance between the camera and the person being photographed can basically be kept at the usual speaking distance.

Baidu encyclopedia-monitoring camera

How to adjust the focal length of video with easy3d camera

Hello, Easy3D camera can focus the video as follows:

1. First turn on the Easy3D camera, and then click the "Settings" button to enter the settings interface.

2. In the setting interface, find the "focus" option, click it, and you can see the slider for adjusting the focus, which can be adjusted according to your own needs.

3. After the adjustment is completed, click OK to complete the adjustment.

4. Finally, you can take a video to see the effect of adjustment.

I hope the above answers can help you solve the problem, thank you!

How to adjust the focal length of SLR camera

1. Adjust the aperture first, and then turn the gear left and right to adjust the aperture. The maximum or minimum pore size is not necessary. You can adjust it to 5 first. At first, the default value of the camera is 5. Take this value first, and then adjust it to 13 if it is fuzzy.

2, focus or focus, focus-refers to changing the image distance v, that is, changing the distance from the optical center of the lens to the bottom surface. So as to obtain a clear image of the object. We know the principle of lens imaging. For example, there is always a clearest position on the screen (camera negative or photosensitive element), which is where the light is concentrated. Countless points make up a plane, which is called focal plane. (focusing is to change the front and back position of the focus! ) Except for some low-grade camera lenses that have no focusing mechanism and can't change the image distance, all lenses can change the image distance regardless of focusing or zooming, so as to get clear images.

How does the camera focus?

There are two ways to adjust the focal length of the external camera of the desktop:

One is the common manual focusing, and the outer ring in front of the lens can be rotated to fine-tune the focal length.

The other is an autofocus camera, which does not need to adjust the focal length.

The built-in camera of notebook computer is fixed-focus, and the camera can't focus unless you use a peripheral camera connected by USB.

You can use the following methods to adjust the focal length of the computer camera to make it clearer:

1 First of all, when you find that the computer camera is not clear, first adjust the focal length of the camera to see if it is not clear due to the settings of the camera itself. Turn the knob on the front of the camera to adjust the focal length of the camera.

2. The camera driver is not normal. You can download software such as the driver wizard to check or update the computer driver comprehensively. You can rotate the circle on the camera first, which is used to adjust the focal length, and then adjust it to the right. Then use the settings in the self-contained software to set some parameters such as brightness and contrast until you are satisfied.

Extended data:

Methods of setting computer camera parameters:

1, first open the software PotPlayer, and then operate in turn as shown in the figure: turn on the camera/other equipment.

2, and then you can see the picture image from the camera.

3. Then, you can right-click and select Properties to view the resolution of the current camera screen.

4. If you are not satisfied with the current resolution, you can set the resolution of the camera and let it output. Action: Open device settings.

5. Then in the pop-up window, you can set the resolution and encoding format of the camera. It should be noted that UVC cameras can basically support MJPEG format, and some cameras support H.264, YUV and other coding formats.