Why does the camera take a rectangular view instead of a square?

1, the viewfinder of the camera is physically divided into optical viewfinder and electronic viewfinder; Structurally, there are eye-level framing, waist-level framing, LCD framing and adjustable viewing angle framing. However, no matter which framing method, the shape is determined according to the coverage of the sensor image field;

2. At present, the sensors of most cameras are rectangular, such as middle frame 53.4X40mm, Quan Huafu 36X24mm, half frame 23.5X 15.6mm and so on. , all in 3: 2 or 4: 3. In order to keep consistent with the coverage of the sensor image field, the viewfinder is rectangular (some cameras use circular eyepieces, but the field of view is still rectangular);

3. Some medium format sensors use the size of 6X6cm, and the viewfinder is square;

4. Although the camera of some 3: 2 or 4: 3 sensors can be set to the frame of 1: 1 or 16: 9, when taking electronic photos, what you see can be changed at the same time, but other image fields are shielded, and the actual image field of the sensor is still rectangular, but the optical photos cannot be changed;

In short, the shape of the viewfinder depends on the shape of the sensor (or film).