16
votes

Theories:

  • that the processing hardware gets hot, so the limit extends the life
  • EU classification of camera as camcorder attracts duty
  • FAT32 file size limit of memory cards is 2gb, but then you could chain the recordings seemlessly together "spanning" and have a playlist metafile to link them (how do PVRs cope)
  • size of memory card, well just get a bigger one?

Is this limitation still prevalent, are there DSLRs out there prosumer and entry that don't have the limit. And why do those that have it, well have it?

9
votes

As far as I know it is a legal thing to prevent extra import duties in the EU. Until Canon or anyone officially state that, it will remain speculation.

It's not a heat issue, as a) if the sensor had heat problems they would likely occur before 30 minutes, and b) after one 30 minute capture the camera will allow you to immediately begin another 30 minute capture!

There is a separate limit of 4GB due to FAT32, you actually hit this limit first if you're recording in full HD resolution. Yes manufacturers could work around it by spanning, but what's the point? DSLRs were never designed to be video cameras, for most people the current limitation should be plenty. If you want to record entire concerts/weddings/events from a fixed camera, then a video camera is a better option all round.

I believe there are hacks to the Panasonic GH1 which remove time limits to video recording.

  • 1
    If I were Canon, I would sell the camera with restriction deliberately in the firmware to enable it to sell cheaper without added import duties, and if EU laws are the sole reason, I would offer a free firmware download, or via their open Canon Firmware toolkit (CHDK - chdk.wikia.com ), i.e. open source parts of the firmware that deal with recording duration time, for developers themselves to turn this restriction off, then canon wouldnt be liable. – therobyouknow Aug 3 '11 at 14:19
  • 4
    But why go to all that trouble? The original purpose of the video feature added to the 5D mkII was to allow photojournalists to capture short video clips to upload to the web so they could do double duty whilst in the field. That was it. Hence no 24fps or 29.7fps modes. The whole video DSLR craze caught them by surprise a little, but even the serious filmmakers using video DSLRs wont have a problem with a 30 minute limit - when was the last time you saw a film with a 30 minute take? – Matt Grum Aug 3 '11 at 15:06
  • 10
    In short, the only people who are likely to care about there being a 30 minute limit are those who want to plonk the camera on a tripod and record their kid's graduation ceremony or whatever. If you're going to do that, you probably don't want shallow depth of field anyway so you might as well buy a cheap video camera that will go for four hours. – Matt Grum Aug 3 '11 at 15:08
  • 1
    what Matt says. No serious videographer is going to want to use a DSLR to shoot for more than a few seconds (I one-up him here, I know), and most casual users will start finding it cumbersome after a few minutes and throw away the results anyway because of the camera shake, poor dof, and other things in which their video isn't what they'd expected after seeing the home videos shot using real videocameras on America's funniest once too often. – jwenting Aug 4 '11 at 8:05
  • +1 x 2 Matt Grum on comments and +1 on answer for confirming my guesses in my question and for the point on longer single-shot footage times not being necessary in most film situations. For me, it's not a deal-breaker to have such a restriction as I would tend to work on short films and music videos. – therobyouknow Aug 4 '11 at 11:43
13
votes

From Beginner's guide to HD video on dpreview.com

Clip limits

One of the main disadvantages with using a stills camera to shoot movies is the short recording times available for HD video; Nikons limit a single take to 5 minutes while Canons and European Panasonics stop after 29 minutes, 59 seconds. This limitation is due to the different (European) import duty rates for still and video cameras. However, although this may seem like a handicap, in reality you would never need to shoot a sequence for longer than a couple of minutes or so (The celebrated opening take of Orson Welles' 'Touch of Evil' calls it a day after just three and a half). Look at any program or documentary on TV and notice that most shots are only held for a few seconds. Furthermore, a 4Gb card will store just 12 minutes of 1080p video from a Canon 5D Mark II, so you may never hit the 29 minute limit. The only time you would possibly need a longer recording time is in the case of shooting an entire wedding ceremony or event, in these situations a camcorder may be a better option.

  • +1 for the answer @kristof. For me, it's not a deal-breaker to have such a restriction as I would tend to work on short films and music videos. – therobyouknow Aug 4 '11 at 11:44
  • 9
    There is a bit of mythbusting to do here! Shots shown on TV and in films are rarely more than a minute, a couple max. However, professionals often take long takes in non-staged situation such as live-events, interviews, sport matches, etc. Someone does NOT start and stop the camera every few seconds. What happens is that the long footage gets chopped into short shots (removing uninteresting parts) that are assembled into a video or film which is why we rarely get to see shots longer than a few minutes. If you have the luxury of being able to yell 'Action' than you are in another ball-camp. – Itai Aug 4 '11 at 12:43
2
votes

The real reason in the canon case is the license for the codecs. If you go past the 29:59 then you are required to have a license per unit.

http://www.mpegla.com/main/default.aspx

http://www.businesswire.com/portal/site/home/permalink/?ndmViewId=news_view&newsId=20090705005026&newsLang=en

Wav files are limited due to the 32bit code and thus limited based on size.

  • 1
    +1 Thanks @bod dodd. It's a shame that artificial restrictions such as this get in the way. Solution might for camera makers to offer the patent and royalty free open source WebM format for recording (at a high quality bit rate setting) as well as MPEG. – therobyouknow Mar 13 '12 at 8:35
1
vote

The 4GB filesize limit is the FAT32 file size limit so the camera is unable to record any more. Any time restrictions that are below that limit are manufacturer choices

  • 2
    and as mentioned in the answer spanning, i.e. chaining together multiple files seemlessless during record and playback with an accompanying "playlist" metafile would overcome this. – therobyouknow Aug 3 '11 at 14:16
  • 2
    Given that no serious video will use a single shot length of more than a couple of minutes at most (unless the artistic point of the video is continuous shooting), the manufacturers won't see this as a limiting factor for any serious videographers. Any combining of shots will be done in post processing. Those less serious about video who would want to continuously film something will be less worried about by the manufacturer as it is more of an extra gimmick for them, so they're unlikely to find that a workaround is needed for the file limit – Dreamager Aug 3 '11 at 14:36
  • +1 @Dreamager on comment for adding to the thinking that continuous long duration filming is not necessary – therobyouknow Aug 4 '11 at 11:36
1
vote

That depends on your DSLR, well any specific camera:

  • Cameras which record in Quicktime, MP4 or AVI format are limited to 2 GB or 4 GB since they output a videos in as a single file.
  • Cameras which record in AVCHD format such as those from Sony and Panasonic simply split the stream into files, so they have no limits other than card size.
  • Certain manufacturers stop at 29:59 on models sold internationally or exclusive to Europe. As Matt said, there is no official reason for this but one can guess.

Keep in mind that a camera may stop before its official limit (if it has one) due to any of the following:

  • Run out of internal buffer due to too slow card write-speed.
  • Internal temperature safety limit exceeded.
  • Battery charge to low.
  • Insufficient power.
  • QuickTime and "MP4" (by which you probably mean the QuickTime-derived MPEG-4 part 14 container format) have no file size limit. AVI does have a 4 GB limit in a lot of programs, though there have been extensions to lift it. – Warren Young Aug 3 '11 at 15:11
  • The key is 'single file'. No camera creates bigger MP4, MPG, MOV, AVI and WMV than 4 GB because they cannot. The file-system used on most flash memory cards (FAT32) wont allow it. – Itai Aug 3 '11 at 15:30
  • 1
    Please read the entire answer. Cameras which use these formats store videos as single files. Those which use AVCHD format store videos as multiple files and therefore can capture longer clips. – Itai Aug 3 '11 at 17:19
  • 1
    +1 Itai for AVCHD multiple files. Presumably it would be feasible for a camera to record footage in multiple, "chained" files in other formats and use an accompanying text file to order them for recording seemlessly. It seems to me that the reasons are more to do with 1) EU laws about duty on cameras classed as camcorders because they have longer recording times 2) overheating 3) limited R&D effort and costs meant that implementing such aforementioned spanning/chaining for non-AVCHD formats for footage over multiple files was not implemented. – therobyouknow Aug 4 '11 at 11:40
  • 1
    +1 @Itai also for the battery life consideration. – therobyouknow Aug 4 '11 at 11:45
1
vote

"limited R&D effort and costs" is the only viable explanation in some camera's. Take the Canon Vixia HF R300. It can record in either AVCHD or MP4. Only on the MP4 recordings there is a time limit of 30 minutes and a size limit of 4GB. Clearly R&D was not allowed to spend the extra effort to span/chain for non-AVCHD formats over multiple files.

  • +1 @Jan Ehrhardt fair point not already covered. Thanks. – therobyouknow Feb 1 '12 at 10:01
1
vote

FAT32 is a non-issue, now that Canon DSLRs have been able to write to exFAT for some time. The licensing restrictions and import duty arguments make sense, though.

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