What's the difference in photography between Quan Huafu and China?

In photography terminology, the word "Quan Huafu" is a new term with the rise of digital photography in recent years. In the film era, according to the specifications and models of the film used by the camera and the imaging frame size of the camera, it can be divided into 135 camera, 120 medium format camera, 4X5 or 8X 10 large format camera. The camera with 135 film was used the most, and the imaging size was 24mmX36mm, and the frame was the smallest at that time. The medium format camera uses 120 film, and there are many formats, such as 645, 6X6, 6X7, 6X8, 6X9 or even 6X 12. Note that the nominal frame size of the 645 camera is 60mmX45mm, but it is actually 56 mm x 43 mm. The actual size of 6X6 frame is not 60mmX60mm, but 56mmX56mm, and the actual size of 6X7 frame is 56mmX68mm. As for large format cameras such as 4X5 and 8X 10, although 4X5 and 8X 10 refer to their frames, the units are all inches. The actual size of 4X5 inch film is 99.6mmX 125.4mm, and that of 8X 10 inch film is 201.7mmx252.5mm. Of course, there is a 5X7 large format camera, so I won't talk about it here. APS frame appeared in the late film era, which is the abbreviation of Advenced Photo System, and was called advanced photography system in that year. It is jointly developed by Kodak, Fuji fujifilm, Canon Canon, Nikon and Minolta. There are three sizes of APS film: C, H and P. The H type is Quan Huafu (30.3× 16.6mm) and the aspect ratio is 16:9. The C type is blocked at the left and right ends of Quan Huafu, so the aspect ratio is 3:2, and the P type is blocked at the upper and lower sides of Quan Huafu, so the aspect ratio is 3:/.

In the digital age, digital SLR gradually replaced the traditional film SLR, but due to the technological level of CCD and CMOS sensors at that time, the quality and yield of large-size sensors were not ideal, and the cost was very high. Therefore, we have to settle for the second best and use a relatively more mature and economical APS frame, which is also the origin of the half-width machine we often say.