Recording to dual CF and SD cards slows 5d mk3 down?

Hi guys,

Just got a 5D mk3 recently and I was watching one video that said "having a fast CF card and a slow SD card simultaneously in the mk3 will slow CF down to SD's speed".
This doesn't make sense to me. Yes I I chose the option to record to "Rec. to multiple" or "Rec. separately" than yes, it could slow down as it would record to both cards.

But if I have both cards in camera and choose 'Standard" or "Auto switch card" options and select Card 1 (CF) for "Record/play", wouldn't it mean it is recording to only CF card and hence why would it slow down the camera, or it wouldn't?

Any help really appreciated.

I suspect it's just referring to writing new files to both cards simultaneously; if it needs to write to both cards it certainly can't clear an image out of the buffer until it's written to the slowest card, and it probably only works on one image at a time, so for each image it's going to have to wait until the slower card is done before it can move onto writing the next image to the cards.

Unfortunately Canon messed up with the SD card slot in the 5D3.

http://blog.jeffcable.​com …-put-sd-card-in-your.html

yeah, I never really understood it. Why would i want to run out and buy slow SD cards when I already own CF cards? They did the same thing with the 1D series before the 1DX. I don't know if it's to be 'flexible', but I don't ask to borrow other peoples memory cards, so I don't need that flexibility.

YES it is real mucked up. For security I write to both cards (RAW+ JPEG) and a a 7+ frame burst can take 5+ seconds to write to the SD card. Never mind the FPS can drop to about 3.

RMH wrote in post #17609088
yeah, I never really understood it. Why would i want to run out and buy slow SD cards when I already own CF cards? They did the same thing with the 1D series before the 1DX. I don't know if it's to be 'flexible', but I don't ask to borrow other peoples memory cards, so I don't need that flexibility.

Not sure what your train of thought is but there are photographers who need the redundancy, it's just unfortunate that Canon did not see fit to equip the 1D series with dual CF slots or at least make the SD card slot support higher speeds.

no the redundancy is great, just makes no sense to add a SD card slot to the 5D when many of those upgrading to it (from 5D I/II, 7D, etc) probably have multiple CF cards and no SD cards. They finally got that right in the 1DX at least.

Ok guys I am a little confused.
Yes it is clear if the camera If the camera is instructed to write to both cards simultaneously than obviously the slower card will slow the overall burst rates and buffer clearing rates.
However, I like the idea of using 'Auto switch function", meaning the camera will write to SD card only when and if my CF card is filled completely.
Now my question is using it that way should not slow the camera down although there are 2 cards inserted right? (Because it is only writing to CF card).

Van Gogh wrote in post #17609404
Ok guys I am a little confused.
Yes it is clear if the camera If the camera is instructed to write to both cards simultaneously than obviously the slower card will slow the overall burst rates and buffer clearing rates.
However, I like the idea of using 'Auto switch function", meaning the camera will write to SD card only when and if my CF card is filled completely.
Now my question is using it that way should not slow the camera down although there are 2 cards inserted right? (Because it is only writing to CF card).

No, that shouldn't slow the camera. That's how I have the camera set.

There's been a lot of confusion about this issue in some part, I think, to the Jeff Cable blog post that gets recirculated where it gives the impression that just having the SD card in the slot will slow down the write speed. If you're not writing to the SD card, having the card in the camera WILL NOT slow It down.

davinci953 wrote in post #17609430
No, that shouldn't slow the camera. That's how I have the camera set.

There's been a lot of confusion about this issue in some part, I think, to the Jeff Cable blog post that gets recirculated where it gives the impression that just having the SD card in the slot will slow down the write speed. If you're not writing to the SD card, having the card in the camera WILL NOT slow It down.

That is what my own testing suggested as well.
Just having the SD in does not slow camera down unless I am writing to it.

Van Gogh wrote in post #17609533
That is what my own testing suggested as well.
Just having the SD in does not slow camera down unless I am writing to it.

That's been my experience as well. I don't know if Canon added UHS 1 support to the 7D Mark II, or if the dual card design is the same as the 5D Mark III.

If you want SPEED, then avoid putting a SD card in the 5D MK III. Much has been written about
why Canon would put an SD card interface which does NOT support the high speed standard (called UHS – for Ultra High Speed)

Regards,

110yd

110yd wrote in post #17609701
If you want SPEED, then avoid putting a SD card in the 5D MK III. Much has been written about
why Canon would put an SD card interface which does NOT support the high speed standard (called UHS – for Ultra High Speed)

Regards,

110yd

Just having the card in the camera doesn't slow it down. It's only when you're WRITING to the card. If you're recording to both cards, then yes, it will slow down the camera. If you're recording only to the CF card, and the SD card is just sitting in the camera, it will NOT slow down the camera.

I wish people would stop saying don't put a SD card in the camera. Jeff Cable clarified his initial post:

http://www.canonwatch.​com …with-the-eos-5d-mark-iii/

Van Gogh wrote in post #17609404
Ok guys I am a little confused.
Yes it is clear if the camera If the camera is instructed to write to both cards simultaneously than obviously the slower card will slow the overall burst rates and buffer clearing rates.
However, I like the idea of using 'Auto switch function", meaning the camera will write to SD card only when and if my CF card is filled completely.
Now my question is using it that way should not slow the camera down although there are 2 cards inserted right? (Because it is only writing to CF card).

It will NOT slow the camera down until you start to write to the SD card.
There is no reason not to have the SD card in there waiting for when you run out of CF.

I've never heard anyone say that installing an SD card would slow the camera down before this thread. The idea is ludichristmas!


This is part of why it's good to use more than one function of the multiple cards. When redundancy is paramount, write to both cards.

when speed and catching the action is important, use autoswitch to make sure you don't miss a shot changing cards.

Hey, this thread is for the Old masters, we have Davinci and Van Gogh!!!