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Sony is the only company that uses CFexpress Type A cards as recording media, but for some reason, many users of the Sony α series use SD UHS-II cards, and Type A cards are in the minority. On the other hand, many users, including Canon and Nikon, use Type B, which is the same CFexpress. One reason why Type A cards are not used is because they are expensive. Type A cards are positioned as the successor to SD cards, but the price difference between them and SD UHS-II is too large. In particular, the price of a large-capacity Type A card is enough to buy a popular mirrorless camera. The main reason why they are so expensive is that Type A is only used in Sony cameras, so it is difficult to achieve economies of scale (mass production effects). Another reason is that there are few manufacturers that make Type A. Another reason is due to the transfer speed and the associated buffer clogging. When shooting ultra-high-speed continuous shots or high-resolution RAW videos, the difference in transfer speed between Type A and Type B becomes apparent. Roughly speaking, Type B has twice the transfer speed of Type A. However, the difference between Type A and Type B is not so noticeable in normal shooting. That is why SD UHS-II continues to be used. However, the transfer speed of SD UHS-II in actual products is already approaching the theoretical limit of about 312MB/s, and if video becomes more popular in the future, SD UHS-II will struggle. This is because VPG400, the standard for high-speed video shooting, has a minimum guaranteed transfer speed of 400MB/s. For this reason, Sony has equipped almost all of its recent α series mirrorless cameras with Type A and SD UHS-II compatible slots. However, the transition from SD UHS-II to Type A is unlikely to progress any time soon. On the other hand, there is a possibility that the interface standard for CFexpress cards will be in line with the next-generation PCIe4 standard, rather than PCIe3, and at this year's CP+2023, a Taiwanese manufacturer exhibited a PCIe4 CFexpress card (measured at over 3000MB/s, theoretical value is 4000MB). In the future, Type A and Type B recording media will likely coexist, but the superiority of Type B is unlikely to be shaken.