photographer Jeff Cable, to buy 2 Canon 5D Mark III. He likes the setting of the CF + SD card slot, you can use CF card as primary storage, SD card backup, or RAW files can be deposited into the CF card, the JPEG file into the SD card. But after some testing, he concluded: If you want to get the 5D III fastest shooting speed is best not to use any SD card .the
Cable made a further explanation: “… for some unknown reason, Canon 5D III configuration to a high-speed CF card slot support UDMA7 agreement, a standard SD card slot (UHS standard). This is very strange, because a lot of cameras in the last year has been to support UHS1 maximum speed of the UHS SD card can only reach 133x (20MB / s). Yes, even if you are in the camera load 600x SD card, they can only get the speed of 133x. “
if only the slower of the SD card slot, which is actually not a big problem, because we can use the SD card to store smaller JPEG files (such as for real-time sharing), but the real question is: “Camera cache speed will default to the slowest to follow the inserted memory card, so if you insert a CF card for a 1000x, and an SD card, then highest cache speed is only 133x to. for shooting sports or other subjects need to burst, which is unacceptable. “
we have not yet on this issue, validation testing. Just in the studio or general shooting 5D III, does not require high-speed continuous shooting, then you is not a problem, but if you need high-speed continuous shooting, it is best to test your own camera.
However, Canon have released the 5D II firmware upgrade, improved read and write speeds of the UDMA7 CF card. We look forward to soon see the 5D III a new version of firmware.
UHS-I and UHS Speed Class 1 is the SD Card Association released in June 2010, a new high-speed performance logo. SDXC / SDHC products USH-I used to identify the bus interface bandwidth to achieve 104MB / s (does not mean that the actual transmission speed), while the UHS Speed Class 1 identifies the SD card and equipment based on real-time storage of high-definition video.(This article Source: New Photography)
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