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Warbler
15-08-2015, 2:25pm
Doing some research on SD card speeds and stumbled on this video. Pretty geeky and maybe the bloke in it might prefer to do gardening shows, but useful for beginners I think. Unintentionally funny too.

https://www.youtube.com/watch?v=c5gOQj5JhKQ

Warbler
15-08-2015, 4:14pm
Finally! I've been stuffing around for ages trying to get info on slot speeds for various Canon dual-slot models. Having been stung by Canon with its 20mb/sec SD slot in the 5D Mk III, I didn't want to get caught again. I need to replace an existing body and I really can't afford to pay top dollar for another 1 series body with dual CF slots. That leaves just the 5D Mk III which is a bit long in the tooth now or the 5Ds or 5Ds R. Canon are a bit coy with quoting exact specifications for their card slots. Given that SD cards are backwards compatible, simply saying that the camera is UHS-! compliant doesn't mean the slot will run at UHS-1 speeds.

The 20mb/sec figure I used above for the 5D3 was obtained by performance testing a Magic Lantern hacked 5D3. The CF slot came in at 100mb/sec. There has always been a noticeable drop off in speed for me when shooting to the SD card instead of the CF card even taking into account the 1000X speed of the CF card and the 600x speed of the SD card.

From a review on Imaging Resource website here: http://www.imaging-resource.com/PRODS/canon-5ds-r/canon-5ds-rA.HTM I found this paragraph:

"Like the 5D Mark III, the 5DS R includes dual card slots -- one CompactFlash and one Secure Digital -- however, unlike the Mark III, the SD slot in the 5DS R is UHS-I compliant. Also, given the same body design as the 5D Mark III, all the standard Canon accessories, such as batteries and vertical grip, are compatible with the 5DS R. And as with the 5D Mark III, the estimated shutter durability is rated at 150,000 cycles."

Given I have to buy my gear without getting to put my grubby hands on it beforehand, I really didn't want to get bitten again. Even the 6D's SD slot is rated at twice the speed of the 5D3's speed.

Here's a link to the Magic Lantern Forum Discussion:

http://www.magiclantern.fm/forum/index.php?topic=12630.0

Now I just have to decide whether $3800 for a 5Ds R can be stretched to $5600 for the soon to be replaced 1Dx. I guess that $5600 will drop again as soon as the 1Dx Mk II arrives in October.

- - - Updated - - -

This might be better placed in another part of the forums. Sorry. I didn't read the sticky first.:Doh:

ameerat42
15-08-2015, 4:25pm
Very informative:th3:

Nope. Good enough here.

Ta.

Warbler
15-08-2015, 4:48pm
According to this site https://www.pretzellogix.net/2014/10/24/a-list-of-all-uhs-ii-sd-cards-readers-and-cameras/ there are very few digital cameras around that will handle UHS-II cards. The rest that handle UHS-I will not exceed 104mb/sec according to the SD Association here https://www.sdcard.org/consumers/speed/bus_speed/index.html

Notice that UHS-II has extra pins that UHS-I doesn't.