7D maximum sustained recording length?

[Dan Brockett]

Hi Jim:

The 5D MKII doesn't arbitrarily stop recording at 12 minutes, it stops recording at 4GB. Since the H.264 codec is a variable bit rate, this could conceivably happen at 11 minutes or 16 minutes, depending on the subject, lighting, camera movement, etc.

I have shot interviews with the 5D MKII and had it shut down before at 15 minutes. It just stops recording, the red recording light just stops flashing.

You can immediately begin recording again, but some feel that as the CMOS imager heats up, that the signal becomes noisier, others disagree with this assertion. I need to really eyeball some of my hour long interviews and compare noise levels at minute two versus minute fifty-two.

Dan

[Jim Babcock]

Oops, I had forgotten the 5DMk II uses the CompactFlash chip, not the SDHC one that my Vixia AVCHD video cameras use. What I said applies to the SDHC chip; I don't know if there is a similar 4 gig limit on the CompactFlash file system. I assume there's more difference between the two classes of chips than just physical size.

Re: Stopping at 4 gigs. I wonder why Canon didn't just allow longer video clips to be recorded continuously in 4 gig chunks, like they do with their SDHC based video cameras like the Vixia HF S 100. It's a minor annoyance in post but completely workable. As you said, it may be an overheating issue.

[Peter Burke]

I would have thought FAT32 (4GB file limit) was chosen to service Mac users.

If Macs didn't exist, then the current PC industry standard NTFS file format would be used - ie there would be no file size limit.

Yes, blame the Macs.

[Chris Hurd]

We don't blame the Macs on this site. Or to be more accurate, we don't do platform wars here.

The 4GB cap is not related to the camera's file system.

[Jon Fairhurst]

Originally Posted by Chris Hurd

The 4GB cap is not related to the camera's file system.

The file size is limited to 4GB by the file system. And, yes, FAT32 is used on flash cards for broad compatibility. It's not just Macs. Consumer electronics devices with embedded processors (including cameras) access flash cards these days.

But Canon could have automatically created new files and stuffed them with data so there would be no gaps. The decision to stop when 4GB is reached is entirely Canon's.

[Xavier Plagaro]

Could it be because the CMOS is damaged from prolongated use??

[Dan Keaton]

Dear Jim,

The media itself, such as SDHC and CompactFlash do not have a 4 GB limit. Neither will SDXC.

Fat32 is typically choosen as it allows the widest compatability among computer platforms.

[Brian Luce]

Originally Posted by Dan Brockett

You can immediately begin recording again, but some feel that as the CMOS imager heats up, that the signal becomes noisier, others disagree with this assertion. I need to really eyeball some of my hour long interviews and compare noise levels at minute two versus minute fifty-two.

Dan

Well this would be a good thing to find out. Afterall, interviews are considered this cam's killer app. If this camera doesn't have strong legs, dealbreaker!

[Richard Hunter]

If there is a thermal design issue, most likely it is marginal and only shows up when the camera is at the limits of its environmental operating range. I would not expect it to overheat in an airconditioned room, because then it would not have been able to pass product testing.

Richard

[Michael Rosenberger]

I'll take FCP with a 4gig limit. Blame capitalism, free market, and anti-trust laws.

Anyway...when BetaSP was king we only shot 10 or 30 minute tapes anyway, so meh...

[Keith Moreau]

I'm not sure what people are talking about with Macs and a 4GB limit or if it is a joke among some Mac users (as I am one). Modern Macs use HFS+ and there is no such file size limitation (it's basically unlimited, bigger than any hard drive will be 10 years in the future), nor is there one in Final Cut Pro. Even 10-year old Mac OS had a 2TB file size limit (not sure about FCP). I've captured whole MiniDV and HDV tapes at 12GB and used those files in Final Cut Pro. Most camcorder manufacturers use the Fat32 file system to format the flash cards. Also Macs can read NTFS drives, they just can't write to them. Not something you'd necessarily want to do to your flash drive anyway.

The common technique is for the camcorder to stop writing before 4GB and begin writing a new file and then the files are butted together in your NLE. Unless there is some technical limitation buffer or processor power on the 7D while it is finishing closing the file and opening a new one simultaneously, it should be able to do this easily.

The 12 minute limit is quite annoying to think about, since one of the main reasons for me to get a 7D would be for for interviews for the shallower depth of field in tight situations. However, as long as stopping and starting recording again happens fairly instantaneously, I guess I can remember it.

I hope the come out with a firmware update to address this, or perhaps we can pay extra for this feature. I think it would be worth $100 or more.

[Craig Coston]

I just tested out my new 32GB CF card in mine. I noticed the remaining record time when I put it in was 29:59, even though the card should be capable of much longer than that. Is that due to the EU restrictions or is my camera doing something funky?

[Michael Murie]

Craig; what video mode are you in? In standard def the limit for a segment is 29:59. Canon's manual says a 16G card should hold 49 minutes in HD or 1hr39min in standard def, so 32GB should be twice that!

[Craig Coston]

In all video modes. Could it be the card I'm using? I'm using a Kingston Elite Pro 32GB. BTW, for anyone who might be interested, I ran 1080P 24 for 17:24 in a single clip. It doesn't cut off right at 12 minutes. This was a locked down shot though with nothing moving in it just to drain the battery down so I could charge it again for a shoot tomorrow.

[Kin Lau]

30min's is the EU limit. Otherwise it's a video camera, and the taxes go up.