Any issues with writing to CF AND SD card at same time?

ajax_andy

ajax_andy

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I bought the 5D MK III recently and my entire memory card collection is CF cards due to having the 7D as my main body before.

I'd ideally like to use the dual card slots in the 5D to write to my CF cards but also a SD card too just as a back up in case anything ever went wrong with the CF card mid wedding.

However would this impact on the FPS the camera shoots at? I use 60MB/s CF cards normally but do have a few 30MB/s cards too and I'm worried adding a SD card in to the mix too may cause write speed issues especially if paired with a 30MB/s CF card.

Anyone know if there's going to be an issue here?
 
Doubt it but the camera will write to the cards at the lowest card speed.
 
The 5D3 does not support UHS on the SD card so is limited in speed.

You will find that up until the buffer is full you'll see no difference (obviously)
However, once the buffer is full you will write to the cards at the rate of the slowest card (the SD card) so you'll be crippling the speed of flushing the buffer.

If you don't shoot quickly enough to fill the buffer and some, there is no real issue.
If you shoot JPEG, it's less of an issue as the files are smaller.

It appears that many people installed both card, but only shoot to the CF card and then manually duplicate across to the SD card when they are quiet to keep the buffer clearing speeds up.
 
PistolPeteUK said:
The 5D3 does not support UHS on the SD card so is limited in speed.

You will find that up until the buffer is full you'll see no difference (obviously)
However, once the buffer is full you will write to the cards at the rate of the slowest card (the SD card) so you'll be crippling the speed of flushing the buffer.

If you don't shoot quickly enough to fill the buffer and some, there is no real issue.
If you shoot JPEG, it's less of an issue as the files are smaller.

It appears that many people installed both card, but only shoot to the CF card and then manually duplicate across to the SD card when they are quiet to keep the buffer clearing speeds up.
Click to expand...

Thanks for the reply :)

Tbh I can't imagine ever shooting at 5 frames a second as i'm not shooting fast moving sports or the like... so assuming that I don't go above more than my usual one shot a second at the most (not sure I ever even fire off shots that quickly) I shouldn't notice any drop in write speeds if I add an SD card in to the mix too?
 
At that rate you won't notice.

I use fast CF cards in slot 1, small ones to change frequently, and a 32Gb class 10 SD card as backup, raw files recording to both. I've never had an issue in real world shooting, obviously with my main landscape work it would never be an issue but I've shot weddings and events with my 5D3 and haven't had a problem with slow buffering.
 
I've started saving my raw files to the CF card and Jpeg files to the SD card and I don't machine gun shoot so never have any problems. I've got mine set to silent shutter most of the time and that slows the frame rate down but it's still plenty fast enough for me. I've got 5 16Gb Cf cards and a couple of 16Gb SDHC cards and for the amount I shoot, a lot of the time I just shoot Jpeg only if the shots aren't too important (for my own pleasure shots) so they are plenty.
 
I'm regularly hitting the problem at weddings. Mainly because using a video light or other scenarios away from the ceremony where the light is low & consequently so are the shutter speeds I shoot in small bursts of 3 frames. Very quickly 3 frame bursts become 2 & even 1 as the buffer struggles to clear. I've had it at lively confetti shots as well.
Its very annoying but I'm not aware of a way around it
I write RAW to both cards, 60mb/s CF & 45 mb/s SD
 
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paul_g said:
I'm regularly hitting the problem at weddings. Mainly because using a video light or other scenarios away from the ceremony where the light is low & consequently so are the shutter speeds I shoot in small bursts of 3 frames. Very quickly 3 frame bursts become 2 & even 1 as the buffer struggles to clear. I've had it at lively confetti shots as well.
Its very annoying but I'm not aware of a way around it
I write RAW to both cards, 60mb/s CF & 45 mb/s SD
Click to expand...

Do you think writing to both is slowing things down then?
 
ajax_andy said:
Do you think writing to both is slowing things down then?
Click to expand...

Yes take the SD card out & the problem goes away.
It is annoying but I've got used to it now & it is only those scenarios it shows up in. I'll live with that for the peace of mind of having 2 sets of irreplaceable files
 
paul_g said:
Yes take the SD card out & the problem goes away.
It is annoying but I've got used to it now & it is only those scenarios it shows up in. I'll live with that for the peace of mind of having 2 sets of irreplaceable files
Click to expand...

Your problem is the SD card speed. As I pointed out earlier the camera will write to both cards at the slowest card speed so in your case it will write at 45mb/s.

I would say 45mb/s would be the min card speed for pro shooting nowadays. Also the larger the card the faster it is due to having more sectors.

Buy a faster card is the answer.
 
admirable said:
Your problem is the SD card speed. As I pointed out earlier the camera will write to both cards at the slowest card speed so in your case it will write at 45mb/s.

I would say 45mb/s would be the min card speed for pro shooting nowadays. Also the larger the card the faster it is due to having more sectors.

Buy a faster card is the answer.
Click to expand...



There's loads of contradictory information out there but a quoted figure is that the SD card slot is limited to 133x which I believe is about 20mb/s so a faster card won't make any difference. Having read that I haven't bothered trying but it may be worth a punt on an extreme pro to see
 
paul_g said:
There's loads of contradictory information out there but a quoted figure is that the SD card slot is limited to 133x which I believe is about 20mb/s so a faster card won't make any difference. Having read that I haven't bothered trying but it may be worth a punt on an extreme pro to see
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Why would Canon limit the write speed to 20mb/s?
 
admirable said:
Why would Canon limit the write speed to 20mb/s?
Click to expand...

Dunno
Maybe I shouldn't believe what I read on the internet :D

Edit: Just seen Pete's post above where he states the SD slot isn't UHS compliant. Why they did it who knows, but they did :thinking:
 
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Who knows why anyone makes the decisions like this - marketing, cost, availability of parts, time to market considerations.....

Why didn't they make it UHS compliant
Why didn't they use 2x CF slots
 
I don't have a 5DIII so I phoned someone who has. Shooting Raw to both cards he gets about 10 frames before the buffer start filling and slows things down.

He uses sandisk pro cards but did mention it seemed faster writing raw to both cards than raw to CF and jpeg to the SD card............seems strange but he was convinced that was the case but hasn't tested it.
 
admirable said:
I don't have a 5DIII so I phoned someone who has. Shooting Raw to both cards he gets about 10 frames before the buffer start filling and slows things down.

He uses sandisk pro cards but did mention it seemed faster writing raw to both cards than raw to CF and jpeg to the SD card............seems strange but he was convinced that was the case but hasn't tested it.
Click to expand...

Interesting he thought it worked better shooting raw to both... I'll probs just buy an SD card and do some tests outside of a wedding or other shoot and see how it goes :)
 
ajax_andy said:
Interesting he thought it worked better shooting raw to both... I'll probs just buy an SD card and do some tests outside of a wedding or other shoot and see how it goes :)
Click to expand...

If you're shooting weddings you need your head examining not using both card slots.
But thats just the opinion of someone who shoots weddings full time & did once have a card fail
 
paul_g said:
it just gets to 20Mb/s which backs up the site I'd seen.

using the camera set up for my video light shots I don't quite get 3 bursts of 3 frames off before things slow down.
Click to expand...

133x or 20Mb/s is the spec I have read too.
 
PistolPeteUK said:
Who knows why anyone makes the decisions like this - marketing, cost, availability of parts, time to market considerations.....

Why didn't they make it UHS compliant
Why didn't they use 2x CF slots
Click to expand...

Maybe they didn't want to hurt 1Dx sales :D

Apart from the speed issue with the 5D I like the CF/SD combination.
I keep a set of cards from my weddings until the wedding is fully edited. With the backlog caused by regularly shooting 3/4 weddings a week in the busy months it would cost me a fortune in CF cards!
 
I like CF / SD too.

Means I don't need to take a card reader on holiday, my laptop has an SD slot.
 
paul_g said:
If you're shooting weddings you need your head examining not using both card slots.
But thats just the opinion of someone who shoots weddings full time & did once have a card fail
Click to expand...

I only recently bought the 5D and had been using a 7D prior to this where dual cards weren't possible, and yes I agree that using both is essential which is the point of this thread. I wouldn't want to use the SD card with a 30mb/s CF card if it meant it would cause issues, and would buy faster CF cards to replace the couple of slower one's I have if it will. However i'd rather not if it's not going to impact on the speed and just buy the SD card alone
 
30 mb/s CF cards do sound as if they may be getting on a bit so may be worth replacing for piece of mind but other than that get some SD cards & get shooting. As I said the problem only surfaces in specific circumstances & its easy enough to work around it.
 
paul_g said:
30 mb/s CF cards do sound as if they may be getting on a bit so may be worth replacing for piece of mind but other than that get some SD cards & get shooting. As I said the problem only surfaces in specific circumstances & its easy enough to work around it.
Click to expand...

yeah I'll probs get some faster one's to be on the safe side... cheers for the help :thumbs:
 
Must admit that Ive never had a problem with mine. Shot 10+ weddings with the 5D3 now and never once have I filled the buffer - I am not a spray and pray type shooter, and think I actually only use it on burst mode for the confetti shot...where I might fire off 5-8 frames.

I use a San Disk Extreme in the CF slot (64GB) and a San Disk Extreme Pro 64GB SD Card (45 mb/sec) and tend to keep these in the camera right through the wedding, shooting either mRAW or Full RAW to both
 
futureal33 said:
Must admit that Ive never had a problem with mine. Shot 10+ weddings with the 5D3 now and never once have I filled the buffer - I am not a spray and pray type shooter, and think I actually only use it on burst mode for the confetti shot...where I might fire off 5-8 frames.

I use a San Disk Extreme in the CF slot (64GB) and a San Disk Extreme Pro 64GB SD Card (45 mb/sec) and tend to keep these in the camera right through the wedding, shooting either mRAW or Full RAW to both
Click to expand...

Thanks for the reply... sounds like I should be fine in that case :)
 
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