Can cheap or slow CF cards slow down your bitrate on a MkII or MkIII?

J

James Mills

New member
I've been shooting with the 5D for years and have never heard of cheaper cards effecting the bitrate or quality of one's video until my friend recently told me that the mkII and mkIII have variable bitrates which change while you're shootiing and thus cheap CF cards will disallow the camera from getting its best quality.

Is this true? Your thoughts would be greatly appreciated.
 
James Mills said:
I've been shooting with the 5D for years and have never heard of cheaper cards effecting the bitrate or quality of one's video until my friend recently told me that the mkII and mkIII have variable bitrates which change while you're shootiing and thus cheap CF cards will disallow the camera from getting its best quality.

Is this true? Your thoughts would be greatly appreciated.
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When you use it "as advertised" out of the box, then faster cards are not that necessary for either stills or h264 video. Faster cards do give you faster download time compared to slower ones.

If you use it with magic lantern firmware add-on to shoot raw video, then yes, faster cards is needed as the files created are large. Around 4gig per 1 minute of Raw video at 24 fps.

Optimally you'd need at least a 1000x CF card to appreciate the full potential of the firmware enhanced camera.
 
James, Your friend is wrong. That is not how it works. There is a plague of technical ignorance combined with arrogance in the worlds of photography and videography. This is how bad information gets spread around. People have no idea what the hell they are talking about, but they come across as a big shot, know it all, and other people believe the crazy that comes out of their mouths.

Canon DSLRs do record video in variable bit rate. However, they also have a recording buffer, so that if the card is not keeping up, you will get a warning first and then recording will stop if the card is to slow. In a nutshell, the camera handles cards that are to slow to record video by stopping the recording, not by recording at a lower quality.

If you check the manual, you will find the minimum card speeds recommended by Canon. If a card meets that specification it will record video continuously until the card fills. If not, the recording will just stop with a buffer full warning.
 
Celluloid Dream said:
James, Your friend is wrong. That is not how it works. There is a plague of technical ignorance combined with arrogance in the worlds of photography and videography. This is how bad information gets spread around. People have no idea what the hell they are talking about, but they come across as a big shot, know it all, and other people believe the crazy that comes out of their mouths.

Canon DSLRs do record video in variable bit rate. However, they also have a recording buffer, so that if the card is not keeping up, you will get a warning first and then recording will stop if the card is to slow. In a nutshell, the camera handles cards that are to slow to record video by stopping the recording, not by recording at a lower quality.

If you check the manual, you will find the minimum card speeds recommended by Canon. If a card meets that specification it will record video continuously until the card fills. If not, the recording will just stop with a buffer full warning.
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Thanks for your thoughts on the matter. Curiously, do you know what the minimum card speed recommendation is?
 
I have only seen a buffer fill up on my 7D when I used the 133x cards that were popular a few years ago. Since decent cards are much cheaper these days, there's no need to buy the slow 133x ones.
 
I will not affect the bit rate for video but you might get error or hang up when recording or just stop recording when without any notice.


I have been happily shooting with the 233x CF card for 5D2 for the previous many years.

You will need a longer time to "reload " when you are shooting jpg still or raw still

Also 5D2 do not support the newer Hi speed card. 5D3 is ok though
 
There was once a rumor that an UDMA CF card got better image because it let the 5d offload some of the encoding. Was there any truth to that?
 
maarek said:
There was once a rumor that an UDMA CF card got better image because it let the 5d offload some of the encoding. Was there any truth to that?
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No. Not true at all. And if you think about it for just a moment, I think you will see the fault in that logic. Just how exactly would a CF card take some of the computing load off of the Digic chip in a 5D? Not picking on you at all, I realize you are just asking about something that someone else said, but that is one of the dumbest things I have ever heard in relation to DSLR video. Run, don't walk away from someone who says such things, because everything else that they say is suspect.
 
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