Fastest SD card I really need for a Canon EOS 6D?

[Wayland]

I'm trying to work out what the write speed of a Canon EOS 6D to the SD Card is.

I've looked around on lots of the reviews but no one seems to actually know the speed of card required.

It's all very well saying "buy the fastest" but often the bottleneck is the write speed coming from the camera.

Given that I will be buying several 16 - 32 gig cards I don't want to pay top price for speed the camera cannot actually use.

(I'm not even faintly bothered by the read speed as I can go and do something else while downloading onto the computer.)

Does anybody know where I can find this info?

[inkista]

From the Canon USA website specs on the 6D:

Recording Media
SD card, SDHC card, SDXC memory card

* Compatible with Ultra High-Speed (UHS-I) memory cards.

Does that help? UHS-I cards are faster than Class 10 cards by a factor of 5 or 10 (depending on the clock speed used); i.e., 50MB/s or 104MB/s. I think you could probably pick any speed card you feel is sufficient for your needs.

[Wayland]

UHS-I cards are backwards compatible to some extent so the fact that the camera can use them doesn't indicate the write speed unfortunately.

The closest info I can find is a test on the EOS 5D III on the Rob Galbraith web site

http://www.robgalbraith.com/bins/camera_wb_multi_page.asp?cid=6007-12452

This test shows little real difference between the Sandisk Extreme and the faster, more expensive Extreme Pro for example.

The 5D shares the same chip as the 6D so it may share that performance but the 5D exhibits much higher performance on it's CF card speeds and since the 6D does not have a CF socket does that mean that the write speeds will be faster.

That's the information I am trying to find but with no luck so far.

[inkista]

True. But the 5DMkIII can't do UHS-I, so not sure I'd count on it being 100% identical in performance to the 6D on this front. They may both be Digic V, but I have a feeling the peripherals interfaces may rely on other chips on the board.

Maybe just attack this from a different POV? Say, figure out how much speed you'd be happy with, rather than what your camera's top limit is.

[Ken MT]

From DPreview

[Wayland]

Thank you, I had seen that and it does confirm that a top ranking card will work in the camera as specified by Canon.

Sadly, what it does not tell us is whether a card selling at half it's price would do the same.

Fortunately I have just received this reply from Canon UK on the matter:

Dear Mr. Waidson,

Thank you for your request and for contacting Canon.

In reference to your enquiry on the EOS 6D please be advised that we are not provided with the information on the exact write speed from the camera to the card but it is correct that the fastest cards available are not always the best choice looking at the costs.

In the SD/SDHC/SDXC range any speed Class will work, from 2 to 10, but budget-wise a Speed Class 6 card would be sufficient enough to fully use the write speed capabilities of the EOS 6D.

Yours sincerely,

Cheryl Meredith
Canon Services & Support

This seems to be confirmed by my own tests which indicate identical performance between a borrowed Sandisk Extreme Pro 32gb card costing £64 and an Extreme 32gb card costing £39 from the same supplier.

This reply from Canon would indicate that I also could expect exactly the same performance from a Sandisk Ultra 32gb card costing just £27. Less than half the cost of the card that a casual glance at the card manufacturers advertising hype would suggest that I needed to "Never miss the moment.."

Of course the read speed is slower but I have never missed a picture because my desktop computer could not read the card fast enough and I have never been so impatient that I couldn't find something else to do while LightRoom worked away in the background.

In fact, as I always copy and convert my RAW files to DNG format when I upload them I can be fairly confident that the card speed is not the bottleneck at that point either.

On the whole then, as I usually carry a dozen or so cards and I have to now buy SD in addition to the CF that my 5D uses, I think I may have just saved myself about £450 that I can invest in something useful instead.