Physics: The Mystery of Fool's Camera Out of Focus?

The "core secret" of a fool's camera is that the focal length of the lens is small, that is, the lens is convex and the distance between the focal point and the bifocal point is very small. In this way, objects far away from the lens can be clearly imaged on the negative without adjustment. Of course, this is only a basic principle, and the lens design of a fool camera has many unique features.

Fool cameras generally can't take high-quality photos, especially close-up and distant views. This shortcoming will be obvious after the work of the fool camera is enlarged, so photographers generally don't use the fool camera.

"Auto-focus" (AF, abbreviation of auto-focus), also known as "auto-focus", is a function set on the camera, which automatically focuses the subject through electronic and mechanical devices to make the image clear.

The main features of autofocus are high focusing accuracy and convenient operation. Especially for the focus of the subject, autofocus has more advantages, and it is also beneficial for photographers to focus more on their own pictures. Auto focus can be divided into active auto focus and passive auto focus.

Active autofocus mainly measures the distance of an object by emitting infrared rays or ultrasonic waves, and the autofocus system drives the lens to adjust the image distance according to the obtained distance data, thus completing autofocus; Passive autofocus is mainly accomplished by receiving the light emitted by the object and by electronic visual inspection or phase difference detection.

Extended data:

Precautions for use

1, good choice of film. More and more people buy zoom cameras. Take the common Pentax Espio 140 as an example. Although it has a large zoom of 38- 140mm, the aperture is only f/4.8-f/ 12. If you use 100 degree film, the effective distance is only 65432.

2. Composition when taking pictures. Although he is not a great photographer, it is not difficult to take a good photo as long as he pays a little attention to some details.

3. Turn off the flash to shoot the scenery. The aperture of zoom fool camera is small, which often causes the flash to flash in full automatic mode. Please know how to turn off the flash (forcibly prohibit the flash). At this time, the camera will use a slow shutter to expose, so be sure to hold your body steady and press the shutter slowly and easily to avoid vibration.

4. Buy a tripod. The tripod (or desktop tripod) on the market is about four or five hundred yuan, but it is very useful. You can take a selfie of Dont Ask For Help and shoot the night scene with a slow shutter (with the activation of the selfie timer, it won't shake the picture), and it won't increase your burden (the weight is only one or two hundred grams).

Baidu Encyclopedia-Fool Camera