The focal length and distance of the lens when taking pictures.

Matching the focal length of the lens with the optimal distance: viewing angle 3.6mm (super wide angle):1~ 3m, 92-degree 4mm (super wide angle): 3 ~ 5m, 74-degree 6mm (standard1): 5 ~ 8m, 55-degree 8mm (standard 2): 8 ~/kloc-.

Standard lens: the viewing angle is about 30 degrees. In 1/2 inch CCD camera, the focal length of the standard lens is 12 mm, and in 1/3 inch CCD camera, the focal length of the standard lens is 8 mm. ..

Wide-angle lens: the viewing angle is above 90 degrees, and the focal length can be less than a few millimeters, which can provide a wider field of vision.

Telefocal lens: the viewing angle is less than 20 degrees, and the focal length can reach several meters or even dozens of meters. This kind of lens can enlarge the influence of the photographed object at a long distance, but make the observation range smaller.

Extended data

The focal length of the lens determines the imaging size of the object on the imaging medium (film or CCD, etc.). ), which is equivalent to the proportion of objects and images. When shooting the same subject at the same distance, the image with long lens focal length is large, and the image with short lens focal length is small.

According to different uses, the focal length of camera lens varies greatly, from a few millimeters to a dozen millimeters to several meters. Common ones are 8mm, 15mm, 24mm, 28mm, 35mm, 50mm, 85mm, 105mm, 135mm, 200mm, 400mm, 1200mm, etc. And it has a super long focal length of 2500 mm.

Long-focus lens is suitable for shooting distant view, with small depth of field, easy to blur the background and highlight the subject. The long focal length lens of a 35mm camera is usually divided into three levels. The lens below 135mm is called medium focal length, such as 85mm, 28-degree viewing angle, 105mm viewing angle, 23-degree viewing angle and 135mm viewing angle. Medium focal length lens is often used to shoot portraits, sometimes called portrait lens.

135-500 is called long focal length, such as 200mm, viewing angle 12 degrees, 400mm, and viewing angle of 6 degrees. More than 500mm is called ultra-long focal length, and the viewing angle is less than 5 degrees, which is suitable for shooting distant view. For example, the close-up on the court and the shooting of wild animals, because it is impossible to get close to the subject, the ultra-long focal length lens is of great use.