How to adjust the camera back focus to shoot a clearer picture

When it comes to how to adjust the focal length of the camera, I have to explain what is the back focal length. The so-called refers to when the standard lens is mounted, the image of the subject can be exactly on the target surface of the CCD image sensor. When the surveillance camera is shipped from the factory, the back focus is thrown or adjusted. Therefore, in the application of the fixed focal length lens, most of the adjustment of the back focus of the surveillance camera is not required. However, in some applications, when the lens focus ring is adjusted to the limit The image may still be unclear when in position. At this time, in the case where the clear lens interface is correct, it is necessary to adjust the back focus of the surveillance camera. According to experience, in most applications where the surveillance camera is equipped with a motorized zoom lens, it is basically necessary to adjust the back focus.

How to adjust the focal length of the camera is as follows. Install the lens accurately on the surveillance camera. Keep the lens aperture as far as possible (to reduce the depth of field range to correctly find the imaging focus). Zoom the lens to the telephoto position with ZoomIn, take a close-up of an object 10m away, and adjust the close-up image by adjusting the focus. Perform zoom adjustment (ZoomOut) opposite to the previous step to pull the lens back to the Wide state. At this time, the screen changes to a panoramic image containing the above-mentioned close-up object, but the focus adjustment can no longer be made at this time. The image change does not adjust the focus), but prepares for the next back focus adjustment.

Rotate the hexagon socket screw of the front end of the surveillance camera for fixing the back focus adjustment ring, and rotate the back focus adjustment ring (for the surveillance camera without the back focus adjustment ring, directly rotate the lens to drive its built-in back focus ring) until the screen The clearest, then temporarily tighten the hexagon socket head cap screws. Re-push the lens to the telephoto state to see if the close-up object just shot is still clear. In the telephoto state, if the close-up object is already clear, tighten the hexagon socket screw and adjust the aperture to the appropriate position. How to adjust the camera focal length? You're done.