How long until you can turn 7d back on after shutdown

J

jrod81

Veteran
From my understanding the 7d will kick off due to file size somewhere around the 12 minute mark. Simple question that I could not find doing a search: Can you just turn it back on or do you have to wait a few beats?
 
if you're accustomed to the d90, it doesn't work like it did. the d90 had to turn off live view in order for the sensor to cool down. the 5d/7d only stops recording because of its lack of file spanning capabilities. so once it hits the ~4gb limit, its stops recording. but then you can begin recording almost instantly.
 
concerts and some long-winded interviews. I think it's a matter of finding suitable cut points. Having this limit isn't the greatest thing in the world... especially if you are goign to do some un-maned lock down shots, or a long timelapse style shoot or whatever. It's not ideal by any means....
 
Stitching would seamlessly attach another 4GB, then another, and another...until the camera overheated or the CF card filled up.
 
If heat is not an issue why don't they just have a buffer which stores a few seconds of video while the first 4GB file is ended and a new one begun automatically, then it continues, spanning files like it hath not a care in the world?
 
commanderspike said:
If heat is not an issue why don't they just have a buffer which stores a few seconds of video while the first 4GB file is ended and a new one begun automatically, then it continues, spanning files like it hath not a care in the world?
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EU tax laws - it's been discussed elsewhere on the site - but the long and short of it is, anything that records 30 minutes of video continuously is considered a video camera by EU law, and is subject to a 4.9% tax.

The 7D cuts off at 12 min in HD, but in SD it will cut off at 29mins and 59seconds.
 
Luis Caffesse said:
EU tax laws - it's been discussed elsewhere on the site - but the long and short of it is, anything that records 30 minutes of video continuously is considered a video camera by EU law, and is subject to a 4.9% tax.

The 7D cuts off at 12 min in HD, but in SD it will cut off at 29mins and 59seconds.
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I was thinking not so much about EU cameras, but I guess Canon makes just one model for worldwide sale right? They'd have to start doing two versions of the firmware like Panasonic.

But the 12 minute limit isn't anything to do with the tax law.

And spanning files can't be that difficult to achieve technically.

It must be to do with heat.
 
It's not a heat issue.

1. As I said in another thread, what Canon most likely did was use the 4 GB file size limit for FAT32 as the basis for time limit and bit rate. They set 29 minutes and 59 seconds as the maximum length for a 480p clip. They calculated the bit rate needed to fit 29:59 into 4 GB. This was the determined to be the minimum bit rate for their ABR/VBR codec.

2. Since 1080p has far more pixel data to compress, they more or less doubled the bit rate for HD mode to ensure image quality. That's why the time limit is less than half of what it is for 480p. And that's probably also why the bit rates are as absurdly high as they are. If I were one of the Canon programmers, I would absolutely say, "Hmmm, for the HD mode let's double the bit rate just to be safe." The 1.8 to 2.1 MB per second for 480p is already overkill; and the reason why they went with it is, again, because they used 4 GB and 29:59 as their other factors.

3. They decided to be lazy and not implement file spanning. This was their quick and dirty way of enforcing the time limit. I'd be willing to bet that the camera doesn't even have a software function that shuts off recording after the time limit is reached; the camera stops when 4 GB is reached.

4. Why would they do this? I can think of several reasons. First of all, the file spanning would have to be implemented for 1080p mode alone, since there would be no point in enabling it for 480p. Second, they would have to program several functions in the firmware: One specifically for file spanning, one that enables the file spanning when it detects that the camera is set for 1080p, one that stops file spanning after the second 4GB file, and one that makes the camera to stop recording after reaching the 29:59 mark. Sure, those functions might be fairly simple to program, but what would be even easier is to not go through the trouble and just not write them. Third, Canon targets the video function to photojournalists who might have an interest in capturing quick, brief video clips to go with their photos. The camera was not intended as a camcorder replacement, so it was never meant for full-on event videography or interviews. With this in mind, Canon didn't feel the need to implement file spanning in 1080p mode. It's the same reason why they disabled manual controls originally; in an interview with Chuck Westfall, he specifically stated that video was originally completely auto-exposure because Canon felt that their target customer, the photojournalist, wouldn't have much experience with videography and would be more interested in being able to record video as easily and painlessly as possible. (That's, of course, the same reason why consumer camcorders are highly automated.)

5. The idea that the 12-minute time limit is due heat issues simply doesn't make sense. First of all, there have been 5D shooters who have recorded videos for several hours at a time without experiencing ill effects from overheating. Second, there is actually no 12-minute time limit; users have been able to do 14 or 15 minutes, but that's because they've shot scenes with very little motion or detail, thus reducing the actual bit rate. (Remember, the codec is variable bit rate, not constant bit rate.) So the 12-minute time limit is really an approximation based on the nominal average bit rate. Finally, there is no reason to believe that 1080p video produces any more heat overall than 480p video. Yes, the image processor might have to do more work, but as I understand it, heat issues with DSLRs primarily have to do with the sensor, which must constantly read and refresh in order to provide the live feed to the live view stream. I would imagine that that's far more taxing on an integrated circuit than a bunch of downscaling and encoding processes.

Any more questions?
 
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commanderspike said:
But the 12 minute limit isn't anything to do with the tax law.
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I don't understand how you came to that conclusion. If stitching were enabled, the first 12 minutes - 4GB (FAT32 limitation) would seamlessly begin the second 12 minutes and the next and the next until the CF card was full. This would easily exceed 29:59 EU limits. That's how the EU tax laws have everything to do with the 12 minute limit.
 
mhood said:
I don't understand how you came to that conclusion. If stitching were enabled, the first 12 minutes - 4GB (FAT32 limitation) would seamlessly begin the second 12 minutes and the next and the next until the CF card was full. This would easily exceed 29:59 EU limits. That's how the EU tax laws have everything to do with the 12 minute limit.
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Then why wouldn't they just limit it to 29:59 as they do in 480p mode?
 
Nikon thought that five-minute clips were long enough for its photographers, and you guys are complaining about 12 minutes and wondering why it's not 29:59? There's no mystery here: Once again, the 5D Mark II and the 7D weren't designed for us filmmakers and videographers. As much of a step forward the 7D is, Canon still isn't thinking like Panasonic did when they designed the GH1. That's why the GH1 still is a better all-around video camera than the 7D, even though the 7D trumps it in a few key areas like performance.
 
I can concur on that part of the GH1... and why would any major camcorder consider limiting a major feature over a 5 percent tax. That seems pety and well just BS. There's going to be quit a few instances when shooting over 12 minutes is desired...
 
Justyn said:
why would any major camcorder consider limiting a major feature over a 5 percent tax. That seems pety and well just BS. There's going to be quit a few instances when shooting over 12 minutes is desired...
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Why?
Because a 5% increase in tax means a minimum 5% increase in price - which could easily mean reduced sales. And why would a company want to take a tax hit for a feature on a camera which is not it's primary function in the first place? Just doesn't make financial sense. Remember - the 7D is a still camera first and foremost... it is not a 'camcorder.' Unfortunately for the rest of the world, Canon is selling only one model across the board - so while we get the luxury of a PAL/NTSC switchable camera (which Panasonic will not do, apparently) we also get saddled with the time limit, even though it's not intended for the United States.

How many people will not buy the 7D because of it's 12 minute HD limit?
Very very few, I would guess - especially considering you can simply hit record again.
Those who are buying this camera for video use are on the bleeding edge of tech, and will probably be a minority of the sales, so those who would not buy it due to a 12 min limit are probably a minority within a minority.

How many people would not buy the 7D if it's price were to go up (at least) 5%?
Probably many more people than those who are turned off by the 12 min. limit.

According to various reports - Canon reps have confirmed that the EU tax law is the reason for the time limit - and the rationale that was outlined by ydgmdlu above is pretty much exactly spot on from what I understand. The easiest thing to do was to take the allowable time limit, in SD, take the maximum file size available in FAT32 - and then work back from that.
 
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