Monday 12 October 2009

Canon 7D HD movie mode post-production

Some gleanings on the HD movie mode of the Canon 7D, from the user manual.

First, you can't zoom while the movie is being recorded. But you can zoom between takes, like you do any other movie camera. This isn't much of a problem for any classical movie makers who don't zoom while filming.

Second, you can't 'autofocus' while recording. But you can use autofocus and even face detect to help focus just before 'taking'.

And some figures for post on Canon 7D movies.

The Canon 7D records to HD movies (1080p or 720p) at frame rates that can be set to 24, 25 or 30. The real frame rates are...

23.976 fps with the camera set to 24
25 fps with the camera set to 25
29.97 fps with the camera set to 30
50 fps with the camera set to 50
59.94 fps with the camera set to 60

These odd numbers like 23.976, 29.97, and 59.94 are used to make the camera NTSC-friendly. If you're in the PAL world, this isn't a huge problem if you're using FCP. You can 'conform' 23.976 fps to 24 fps in Cinema Tools.

All these frame rates are progressive. The Canon 7D like most DSLRs that shoot HD movies, doesn't support interlaced.

Canon 7D HD movie data rates and disk space requirements are...

1920x1080 - at 24, 25 or 30
You can shoot 12 mins on a 4 Gb Card, 49 mins on a 16 Gb card,
Which is 330 MBytes/min, or 19.33 GBytes/hr,
A 1 TB drive will hold 50 hrs

1280x720 - at 50 or 60
You can shoot 12 mins on a 4 Gb Card, 49 mins on a 16 Gb card,
Which is 330 MBytes/min, or 19.33 GBytes/hr
A 1 TB drive will hold 50 hrs

640x480 - at 50 or 60
You can shoot 24 mins on a 4 Gb Card, 99 mins on a 16 Gb card,
Which is 165 MBytes/min, or 9.9 GBytes/hr
A 1 TB drive will hold 95 hrs

If you plan to edit these files in FCP you need to convert them to Apple ProRes. Apple ProRes comes in five flavours. Three of the top ones are ProRes, ProResHQ and ProRes 4444

When Canon HD movies are converted to ProRes, they take up space as follows...

ProRes - 1080p24 takes up 53 GB/hr
or 18 hrs per 1 TB drive
ProResHQ - 1080p24 takes up 79 GB/hr
or 12 hrs per 1 TB drive
ProRes4444 - 1080p24 takes up 119 GB/hr
or 8 hrs per 1 TB drive

ProRes - 720p50 takes up 55 GB/hr
or 17 hrs per 1 TB drive
ProResHQ - 1080p24 takes up 83 GB/hr
or 11 hrs per 1 TB drive
ProRes4444 - 1080p24 takes up 124 GB/hr
or 7 hrs per 1 TB drive

Note that converting Canon HD movies to ProRes won't make the quality better, They will be editable easily. And colour correction will be easier as well.

If you work on an Avid, you need to convert to DNxHD. In that case, Canon HD movies when converted to DNxHD will take up...

DNxHD 175x - 1080p24 takes up 49 GB/hr
or 19 hrs per 1 TB drive
DNxHD 115 - 1080p24 takes up 74 GB/hr
or 13 hrs per 1 TB drive

Here too, converting Canon HD movies to DNxHD won't make the quality better. But they will be editable easily. And colour correction will be easier as well.

Finally, Canon HD movies don't carry any timecode. So if you're converting to ProRes or DNxHD you need to work with these converts and treat them like your original media. There's no need to 'upgrade' to the original movies. Sort of like XDCamEx or HDV when imported into FCP via Log and Transfer.

In the coming weeks I'll be working on the post of a short film shot on a Canon 7D. So more gleanings on how to do a DSLR video post smoothly will emerge. Keep reading...


13 comments:

  1. hey neil,
    this is easily the most exciting camera in the recent past. i look forward to your tests and posts. if possible, can i can over and see the cam? you really are amazing! - Ajay

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  2. Hi Neil, great post, I am thinking of buying this but just wanted to ask about the following:

    You can shoot 12 mins on a 4 Gb Card, 49 mins on a 16 Gb card,

    Is this uncompressed data, or with a compression?

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  3. Ajay,
    I don't have this camera, but two of my friends have bought them and are shooting with it.

    To answer Moath,
    the movie file from the Canon is compressed.

    Uncompressed HD would be at least 180 MB/sec. A 4 GB SD card would hold just 20 sec of uncompressed HD. Of course, it wouldn't be able to record uncompressed at that data rate.

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  4. Small correction. Yes, you can zoom while recording video. Zoom on Canon EOS 7D is done on the lens and therefore manual. It is not in any way limited by shooting mode, ie photos or video

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  5. Hey,

    Great post. This info should really help.
    Ok, want to know if i can get 7D on hire anywhere? I know people who have bought 5D MK II on hire, but for shooting video it doesnt help much since it only gives 30p.

    Cheers!

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  6. I own a HD Production Company called Saturnalia Productions - http://www.saturnaliaproductions.com/hd-production.php - and have shoot, edited and produced HD content for over a decade.

    I am amazed by the images produced by DSLR cameras. However, the format can be difficult to work with in post production.

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  7. Anonymous12:57 PM

    can I make a professional short film/ music video with this cam ? Since you said it can be edited in Avid.will the channels accept this format ?

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  8. Anonymous3:23 AM

    Thanks for the post,I am about to edit a 90min movie on Avid. the final piece will get 35mm copy ,Do I have to edit in native 7d footage?If theres no timecode so what about the EDL or Avids filmscribe?the filmmakers decided for 1080/24 but what about the 25fps-sound,how do You sync that?
    thanks again

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  9. I've devised a workflow for the Canon 7D where I convert it to 24fps, stripe it with time code and import that TC into Avid so you can work at Avid in compressed Avid format.

    Then you use the timecode to make EDLs and upgrade to the original 7D files converted to Apple ProRes 4444 for further post and a filmout.

    Will know of further challenges when this project is complete. So far, tests have come out fine.

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  10. Great discussion.

    Quick Question: Editing a 7D 24p project on Avid MC 3.5, should the project be 1080/24p or 1080/23.976? Output will be DVD, possibly HDCam.

    Thanks

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  11. Hi i have bought 5d mark2 (shoots 24fps)...i wanted to know which is the right place to find accessories(e.g., rig,mattebox,follow focus,monitor,fluid head etc..)thnx-raj(rajinghverma32@gmail.com)

    ReplyDelete
  12. Hi i have bought a 5d mark2..wanna know which is the right place to source accessories in mumbai(rig,mattebox,follow focus,fluid head,monitor etc..)i am also looking for a dop..who will be comfortable to shoot a film on my camera..thanx-raj(rajinghverma32@gmail.com)

    ReplyDelete
  13. great post, especially how many minutes the footage takes up on the cards

    ReplyDelete

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