topic Re: Will UHS II Work for me? in EOS DSLR & Mirrorless Cameras

Will UHS II Work for me?

Seanac — Thu, 17 Feb 2022 04:44:07 GMT

Hi guys. I’m looking to get a faster SD card so my camera can process images faster and so I can take more continuous photos.

im looking at a 300MBS SDXC UHS-II SanDisk card, I googled if my camera was compatable with UHS II and it says that my camera will not take advantage of it (Whatever that means)… and I googled what cards my camera takes and it says it can take SDXC.

I’m just curious as to what “won’t take advantage of it” means. So if I get the UHS II card how will it perform? Will it be as fast as a normal 300MBS?
My camera is a T6S

Re: Will UHS II Work for me?

AtticusLake — Thu, 17 Feb 2022 08:32:41 GMT

UHS-II is an enhanced data bus for SD cards that gets more speed by using more wires. If you look at the back of a UHS-II card, you will see a second row of contacts on the back, compared to an older SD card which only has 1. Clearly, to use UHS-II, your camera needs to have the corresponding exra row of contacts internally, and the T6S doesn't. So when you insert a UHS-II card into your camera, the second row of pins is just hanging in space. The camera just sees the first row, and will automatically fall back on an older, slower communication method.

In other words, exactly as you've been told, a UHS-II card will work in your camera, but it won't be running in UHS-II mode; in other words, you won't get the benefit of UHS-II. So save your money and get a cheaper card.

This is generally true with SD. SD has gone through several generations of data busses with different speeds. When you put a card in the camera, they start talking to each other in the slowest mode, then negotiate up to the fastest mode that they can both handle. In the case of the T6S, that's UHS-I, which just uses the conventional single row of contacts.

BTW, don't be misled by the "300 MB/S" printed on the card -- that's garbage. Those numbers are the best possible speeds that the card can ever get, when reading data on your PC. If you want to know how fast the card regularly is, look at the speed class. E.g. v60 means 60 MB/s sustained write speed.

Re: Will UHS II Work for me?

Seanac — Thu, 17 Feb 2022 12:57:38 GMT

Thank you

So the 300MBS Card is UHS II and V90, if I put it in my camera I know it will not perform as normal, but is there an estimation of how fast it will be?

Also, the fastest UHS I card I can find is 170MBS V30

Re: Will UHS II Work for me?

Waddizzle — Thu, 17 Feb 2022 13:22:31 GMT

Maximum Read and Write speed is determined by the camera hardware, not the type memory card. A memory card can only slow down a camera. It can never speed up the camera beyond its actual performance specifications.

SD memory cards can enter a degraded performance mode when used in an incompatible device.

Re: Will UHS II Work for me?

Seanac — Thu, 17 Feb 2022 13:34:52 GMT

Alright. So if I buy the 170MBS V30 card whats more important to get a faster card..? The V or MBS? And I understand that the camera I have is also limiting, but I want to get the maximum performance out of it with the best SD card.

Re: Will UHS II Work for me?

Seanac — Thu, 17 Feb 2022 13:37:30 GMT

Correction * a faster card that takes photos more continuously once the buffer is full

Re: Will UHS II Work for me?

rs-eos — Thu, 17 Feb 2022 15:12:12 GMT

For write speeds, the only metric that matters is the card's sustained write speed. On V-rated cards, that gives the sustained write speed. So a V30 card gives you 30 MBps (bytes per second) which is 240 Mbps (bits per second).

For some cards, it's a pain to find out the sustained write speed. You may have to visit the original manufacturer's web page and find any detailed technical specs. As AtticusLake wrote above, values printed on the card are really garbage; they tend to only be the theoretical maximum _read_ speed and thus nothing to do with write speeds.

If your camera averages say 15 MB images and can shoot 4 frames per second, that would be 60 MB worth of data. But the card would max out at 30 MB each second and thus the buffer will start to fill. Eventually the buffer will be full and thus the camera will stop capturing images until it can write out its data.

If doing video, as long as the codec is under 240 Mbps, the V30 card should be OK*

* cards that were not freshly formatted, heat issues, and other factors could lessen the ability to write out all the data.

Re: Will UHS II Work for me?

Seanac — Fri, 18 Feb 2022 15:24:56 GMT

Hi Ricky,

I am not shooting video, I am shooting continuous images and want a card that will maximum my cameras buffer performance, making it so I can take more continuous images.

the fastest UHS I card I can find is the 170mbs V30 card. Do you think this card will work well for continuous photo shooting? I just need a card that will make it so my buffer doesn’t get full as fast, so I can take more images continuously.