Is there a big difference in the size of the photosensitive original with the same 20 million pixels?

It is also a photosensitive original with 20 million pixels, and the size varies greatly.

Definition of photosensitive element size: For photosensitive elements with the same effective pixels, the larger the size, the larger the unit area of each pixel, the better the photosensitive performance, and more image details can be recorded.

Based on 35mm film (Quan Huafu), the following figure compares various representative image sensors. It can be found that even the most common APS (half-size) image sensor has a large enough area, which is obviously different from small digital cameras. The area ratio of the image sensor of a small digital camera (1/2.3 inch) to the APS-C image sensor is about 16 times, which is more obvious than that of Quan Huafu image sensor, about 37 times. The increase of area not only brings different blur effects, but also increases the light received by a single pixel in the image sensor in proportion, so the imaging noise is also reduced. In addition, the range of layers that can be reproduced from white to black (dynamic range) is also proportional to the area and becomes wider.