topic Re: 5D Mark III and SD Card Speeds in EOS DSLR & Mirrorless Cameras

5D Mark III and SD Card Speeds

Sirpopealot — Thu, 03 Jan 2013 21:22:54 GMT

Is there any truth to the claims in this link that the SD Card speeds are limited by the 5D Mark III to 133x?

Canon 5D Mark III and SD Cards

Thanks!

Re: 5D Mark III and SD Card Speeds

ebiggs1 — Mon, 13 Apr 2015 14:58:38 GMT

I don't know but I use name brand cards.

Just don't want any problems! So far, so good!

Re: 5D Mark III and SD Card Speeds

Richard — Fri, 11 Jan 2013 04:17:10 GMT

Hi Sirpopealot,

We are unable to comment on information posted on third party websites. The information I am able to provide is based on information available on the Canon USA website at http://usa.canon.com.

That said, the memory cards in the SD slots do not slow down the camera unless the card is unable to accept input from the camera quickly enough. In such cases, the buffer would become full which would result in an overflow error.

I hope this is helpful,

Richard

Re: 5D Mark III and SD Card Speeds

zim — Sat, 12 Jan 2013 15:05:21 GMT

No Richard, sorry not really helpful. It’s a simple question – Does the camera (5D3) default to the slowest card inserted which would be 133x?

If your going to answer questions by supplying links then there is no point to this forum.

Re: 5D Mark III and SD Card Speeds

p4pictures — Mon, 14 Jan 2013 00:28:41 GMT

EOS Mark III has a UDMA 7 capable CF slot and writes to those kinds of cards very quickly. If you put a UHS-1 type SD card in the camera then it's not so fast at writing since the camera doesn't provide the faster UHS-1 support.

Also in my real world experience if you have an SD card and CF card in the camera then the SD card speed or camera controller speed becomes the limiting factor when writing the same content to both cards simultaneously. Regardless of the model or brand of SD card I have used in my 5D3 I cannot get the same write speeds as I get with a good fast CF card like the Sandik Extreme Pro cards.

Brian / p4pictures

Re: 5D Mark III and SD Card Speeds

John — Tue, 15 Jan 2013 20:15:48 GMT

With just a 400x CF card, my buffer size is 16 photos (full sized raw). When I write to the CF and a 400x Lexar Pro SD card, the buffer drops to 13. I'd go get a 600x SD card but the Internet tells me that will not change the drop in buffer size.

13 is sufficient but I never understood why camera manufacturers don't increase their memory buffer. I suspect it is not a technical limitation but a product differentiation reason.

Re: 5D Mark III and SD Card Speeds

dbltapp — Mon, 13 Apr 2015 14:50:05 GMT

Why not just publish the write speeds for each type of card? That Canon doesn't do that suggests it's hiding something.

Re: 5D Mark III and SD Card Speeds

Peter — Mon, 13 Apr 2015 15:00:36 GMT

5DIII

Compact flash: 100MB/s.

SD: 20MB/s.

Together you can reach 120 MB/s for raw video. That is nice.

Re: 5D Mark III and SD Card Speeds

dbltapp — Mon, 13 Apr 2015 15:30:07 GMT

@Peter wrote:
5DIII
Compact flash: 100MB/s.
SD: 20MB/s.

Together you can reach 120 MB/s for raw video. That is nice.

I'm curious as to where you found those figures, as I've been (unsuccessfully) trying to find those specs for years.

Re: 5D Mark III and SD Card Speeds

Peter — Mon, 13 Apr 2015 16:01:59 GMT

You can try yourself with Magic Lantern and the benchmark function.

Re: 5D Mark III and SD Card Speeds

Peter — Mon, 13 Apr 2015 16:49:23 GMT

1100D, 500D, 550D, 600D, 60D, 5DIII all use the same slow ~21 MB/s for SD.

EOS M, 100D, 650D, 700D, 6D use SD UHS and around ~40 MB/s. With my 6D I get around 43 MB/s write. speed.

Re: 5D Mark III and SD Card Speeds

dbltapp — Mon, 13 Apr 2015 16:59:26 GMT

@Peter wrote:
1100D, 500D, 550D, 600D, 60D, 5DIII all use the same slow ~21 MB/s for SD.

EOS M, 100D, 650D, 700D, 6D use SD UHS and around ~40 MB/s. With my 6D I get around 43 MB/s write. speed.

And, to expand the discussion, for CF cards?

Re: 5D Mark III and SD Card Speeds

Peter — Mon, 13 Apr 2015 18:01:27 GMT

50D 70MB/s.
7D 80MB/s.
5DII 75 MB/s.
5DIII: http://www.magiclantern.fm/forum/index.php?topic=12630.0

There is a difference in video mode and playback mode, so I think I was wrong before about fastest 5DIII CF speed. Check out the link for yourself.

Re: 5D Mark III and SD Card Speeds

TCampbell — Mon, 13 Apr 2015 19:56:16 GMT

Zim, be more practical.

The 5D III has a rather large memory buffer (bigger than most cameras). When you shoot, it's always sending data to the buffer... then writiing from the buffer to the card(s).

For "JPEG" shots, to the SD card slot, the shooting is, for all practical purposes, "unlimited" (you will fill the card capacity before it runs out of buffer space).

If you shoot "RAW" shots, then the camera WILL eventually slow down. But that wont happen until it shoots at least a dozen continuous frames (I think Canon officially claims 13 frames before the buffer slows it down -- but I think in personal usage I think I counted 18 (that's practical because RAW images do "technically" compress... they just don't use a "lossy" compression method like JPEG. In other words you'll seem some variability on this number depending on how well the images compress.)

I have BOTH an SD and CF card inserted in the camera -- generally at all times. I still get the performance equal to, or higher than, the numbers Canon claims even with both cards in the camera.

Not having the 3rd party information to directly scrutinize what they say, my inclination is to disagree (but I'd need to see EXACTLY what they claim to be certain.)

My point about the practicality is this... what are you shooting and how many frames per second do you actually require before the camera slows down. Experienced photographers who aren't shooting action photography will tend to prefer to shoot in RAW, but they usually aren't bursting off shots like crazy. Sports photographers are bursting off shots like crazy... but those who need to know that they can hold the button down for many seconds at a time will set the camera to JPEG mode specifically because the shooting is, for all practical purposes, unlimited (even when using the SD card.)

If you REALLY need "action" photography camera performance... a 7D II or 1D X would be on my list of cameras you should look at.

EDIT: I followed the link to the BorrowLenses website to see what they "discovered" (not exactly a "discovery" - anyone who understands technology would have known this even without performing a test.)

What they claim is that if you not only insert both cards, but also USE both cards concurrently (e.g. tell the camera to write your image to both cards after each shot - e.g. one card is used as a "backup" of the other) then this means the camera can go no faster than the speed of the slowest card. Sure... that's true.

HOWEVER... you wont be able to measure any difference at all... until you fill the camera's internal buffer. Then the delay is based on how long it takes to clear the buffer by writing to the cards. Just writing a single image twice (once to each card) is going to slow things down -- you're making the camera do double the work. This slow down would be percevied even if both cards were operating at precisely the same speed. I suspect this has more to do with the "slow down" than the fact that the SD card is operating in a UDMA 7 slot.

Re: 5D Mark III and SD Card Speeds

Otto — Sun, 17 Jan 2016 18:36:54 GMT

Unfortunately, it defaults to the slowest card/card reader max 133. Solution: remove the SD card and write speed defaults to CF card.

Re: 5D Mark III and SD Card Speeds

Canon01801 — Sun, 05 Nov 2017 03:05:15 GMT

Richard,

Can you you please tell us what happens after an "overflow error" occurs?

The word "overflow" suggests that every time the camera buffer fills up that data will be lost.

The word "error" suggests that filling the buffer is an abnormal condition that the camera can not handle correctly.

Surely it can't be the case that either of those statements are true. It would be a terrible way to build a camera.

Lookibg firward to a clarification.

Thank you.

Re: 5D Mark III and SD Card Speeds

Waddizzle — Sun, 05 Nov 2017 14:35:26 GMT

@Canon01801 wrote:
Richard,

Can you you please tell us what happens after an "overflow error" occurs?

The word "overflow" suggests that every time the camera buffer fills up that data will be lost.

The word "error" suggests that filling the buffer is an abnormal condition that the camera can not handle correctly.

Surely it can't be the case that either of those statements are true. It would be a terrible way to build a camera.

Lookibg firward to a clarification.

Thank you.

This is a rather old thread. If you overflow the buffer, you should regard that condition as an operator error.