Next-generation recording media: CFexpress Type B, Type A, or SD Express? > 자유게시판

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What will the next generation of recording media be like? I have often written about this topic in this blog, but the future is unclear. CFexpress Type B (hereafter referred to as Type B), which is used by Canon, Nikon, Panasonic, and others in their mirrorless cameras, has become the de facto standard. With a high transfer speed of about 1800MB/s, it will likely continue to be used in the future. However, although Type B cards are smaller than conventional CF cards, the drawback is that they take up a lot of space when used in a double slot. For this reason, even among manufacturers that use Type B cards, there are few models that use double slots for Type B. Recently, only the Nikon Z 9 has a double slot for Type B and SD UHS-II. This method makes it easier to allocate space, but the transfer speed between Type B and SD UHS-II is too different (UHS-II is about 300MB/s). For this reason, if you use the double slots for simultaneous recording (backup operation), they will not be completely synchronized. Sequential recording is not an issue, but the speed difference between Type B and UHS-II is noticeable.

On the other hand, Sony has adopted the smaller Type A (hereafter referred to as Type A) of the same CFexpress. The transfer speed of this Type A is about 800MB/sec. It was adopted from the α7SIII, probably with the aim of popularizing Type A. Both of the double slots are compatible with Type A and SD UHS-II, so you can insert either Type A or SD UHS-II. This was a groundbreaking mechanism, but the problem is that the maximum capacity of a Type A card is still only 160GB. For still images, this is enough capacity for a professional to shoot a day, but it's a different story when it comes to video recording. For this reason, it is common sense for professionals to use external SSD storage for video shooting. However, this means that the Type A/SD UHS-II compatible memory slot is not being utilized. Perhaps because of this, Sony has made one slot compatible with Type A and SD UHS-II on the α7IV, and the other slot exclusively for SD UHS-II. Of course, there may have been a reason to reduce costs, but it seems to me that Sony is struggling with Type A.

As for the SD card camp, it is also struggling. UHS-III (with a transfer speed of 600MB/sec or more), which follows UHS-II, has not been adopted by any digital camera. One of the reasons is that the next-generation standard called SD Express has already been formulated. As the name suggests, SD Express uses the same PCIe interface as Type A and Type B cards. And the transfer speed is about 2000MB/sec in one lane and about 4000MB/sec in two lanes, which is faster than Type B. However, SD Express is not without problems. One is the compatibility issue. Even if you insert an SD UHS-II into an SD Express card slot, it will only work as UHS-I (with a transfer speed of about 150MB/sec). In other words, it is not compatible with UHS-II because the contact points are in different positions. Another problem, which is also common to CFexpress, is the problem of heat generation. SD Express is said to generate the most heat, and this problem does not seem to have been solved yet. For this reason, no manufacturers are currently using SD Express in digital cameras. Most manufacturers are limited to SD UHS-II, and even high-end models have dual UHS-II slots (except Sony). In my personal opinion, if the heat problem can be resolved to a certain extent, it would be best to use SD Express. The next best option would be a dual slot for Type B and SD Express, but this could cause problems in the circuit design. So, each camp has its own challenges with the next generation recording media, and it seems like they are waiting to see what happens.

Postscript Panasonic will release the LEICA DG SUMMILUX 9mm F1.7 ASPH., a large-aperture ultra-wide-angle lens for the Micro Four Thirds standard, on June 23rd. The price is 60,940 yen (tax included). It is a prime AF lens with an angle of view equivalent to 19mm in 35mm format, and is characterized by its high cost performance. Another feature is the short minimum shooting distance of 0.095 meters. The lens consists of 12 elements in 9 groups, including two ED lenses and one UHR lens, with seven aperture blades and a filter diameter of 55 mm. The size and weight are 60.8 x 52 mm and approximately 130 grams.

JPEG straight out of the box. Taken in May 2019 in the Japanese garden of Showa Memorial Park. The recording media for this camera is XQD, the predecessor of CFexpress Type B. Nikon adopted this recording media from the Nikon D4, and inherited it in the D4S, D5, and D500. With the D6, it became a compatible double slot for XQD and Type B. Even XQD generates a little heat, and I have experienced it getting hot when I released the shutter continuously. Nikon D500, AF-S DX VR 18-300mm F3.5-6.3G, aperture f8, 1/500 sec, AWB, ISO auto.