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Flicker in Panning Shots- 5D MK3

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Nick Zaire
Flicker in Panning Shots- 5D MK3
on May 29, 2013 at 7:37:02 am

Hello!

I've only recently started learning the basics of filming video with a DSLR. The experience has been very interesting, but I have noticed a problem in several videos involving flickering upon playback.

Unless I pan EXCEPTIONALLY SLOWLY, there is a persistent flicker throughout my videos upon playback. At times, horizontal lines are also appearing as part of the flickering.

I've uploaded two samples to demonstrate the issue-



and



. The problem is more noticeable in the first video.

The camera is a 5D MK III w/Canon 24-70 2.8L lens. I'm shooting with a very flat picture style. The camera is mounted on a Manfrotto 701HDV tripod head. The issue is there in the original MOV that is recorded from the camera, and in MP4 (H.264) and MOV (H.264) exported from Premiere Pro CS6.

Is it related to the rolling shutter of the 5D? It is not the same as the very obvious distortion that comes from either a fast pan or filming a fast moving object, but is just as distracting to watch.

Any suggestions or information would be greatly appreciated. Thank you.

(I'm hoping to use the camera with both a slider and glidecam in the future, but I'm a little disconcerted about how it handles motion!)


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Ryan Holmes
Re: Flicker in Panning Shots- 5D MK3
on May 29, 2013 at 3:35:15 pm

What were your settings when you shot? It looks like you probably had the shutter speed set too high for the frame rate you were shooting.

If you're shooting 24/25 fps your shutter speed should be set at 1/50 (technically for 24fps you should be at 1/48 but DSLR don't offer that so 1/50 is as close as you can get). If you're shooting at 30fps you're shutter should be set at 1/60. Basically the rule is your shutter speed is double the fps, or what is called a 180 degree shutter angle. You'll probably want to read more about it:
http://photo.tutsplus.com/articles/shooting-articles/quick-tip-how-does-shu...
http://en.wikipedia.org/wiki/Rotary_disc_shutter
http://hd-slr.com/2011/03/180-degree-shutter-know-the-rule-break-the-rule/
https://vimeo.com/18564104

You can use a higher than normal shutter speed, but you'll need to take into account the effect it produces. It may be more or less pronounced depending on the footage you're shooting. If you have a lot of movement (sports, pans, etc.) you'll tend to notice it more....which, again, may be intentional. But if you're looking for smooth and slightly softer (i.e. motion blurred) video then stick to the 180 degree rule.

If you need to adjust exposure while following the 180 degree rule then you're looking at f/stop, ISO, and ND filters to control light.

Ryan Holmes
http://www.ryanholmes.me
@CutColorPost


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Nick Zaire
Re: Flicker in Panning Shots- 5D MK3
on May 30, 2013 at 1:23:22 am

Thanks for the prompt reply Ryan.

The footage was shot at 1/50 shutter speed- everything I've read stresses the 180 degree shutter rule so much that I've never tried shooting at anything other than 1/50th (25p).

I was actually going to try 1/60 (30p) to see if there was any differences, and even try a range of shutter speeds to see if there was any change to the image 'FLICKER'.

I don't have the exact settings for that footage, but the issue seems to occur for a range of aperture and ISO settings and focal lengths; shutter speed is always set at 1/50th.

The problem has got me somewhat concerned- I want to be more mobile with the camera (sliders, crane and glidecam) but I don't seem to be able to get past the flicker (unless I am exceptionally slow with panning, in which case the footage is fine). I know the camera should be able to do it- watching videos of shoulder-rig mounted 5D's, glidecam footage etc demonstrates that it is achievable.


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Ryan Holmes
Re: Flicker in Panning Shots- 5D MK3
on May 30, 2013 at 4:39:58 pm

[Nick Zaire] "The footage was shot at 1/50 shutter speed- everything I've read stresses the 180 degree shutter rule so much that I've never tried shooting at anything other than 1/50th (25p)."

If this is indeed the case, then I'd say Warren's response is exactly right. Judder - the great downfall of 24p! :-)

It's not so bad, but you do need to be aware of it while shooting. Here's some additonal info on judder for you:
http://www.hdvideopro.com/technique/miscellaneous-technique/help-desk-did-i...
http://blog.abelcine.com/2012/01/10/24p-judder-and-60i-conversion/

The articles I referenced are talking about 2 aspects of judder. (1) Judder that exists inherently in 24fps footage. (2) Judder that exists (and can sometimes be mitigated by) converting from 24p to 60i. So you're dealing with two slightly different but related things.

I think the "solution" proposed in the first article is good. However, I still shoot a lot of material at 24p. You just have to learn it's limitations (same with 30p or 60p or 60i).

Ryan Holmes
http://www.ryanholmes.me
@CutColorPost


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Warren Eig
Re: Flicker in Panning Shots- 5D MK3
on May 30, 2013 at 4:25:54 pm

I think what you are seeing is called Judder. It happens because 24 frames is 4 frames faster than "persistence of vision." When you pan and there are objects close to the lens, you will notice the judder becoming more pronounced. It happens when you shoot 35mm film as well. This is why on a movie shoot you will often see someone wipe past the camera in the opposite direction, during a pan to hide the judder, i.e.. a waiter moves across frame in the opposite direction of the pan.

Warren Eig
O 310-470-0905


email: warren@babyboompictures.com
website: http://www.babyboompictures.com


REEL: http://www.babyboompictures.com/BabyBoomPictures/Reels.html




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Nick Zaire
Re: Flicker in Panning Shots- 5D MK3
on May 31, 2013 at 5:05:14 am

Thank you both for your replies.

The 'judder' seems to be an apt description and explanation of the issue. Understanding the limitations of the hardware, and subsequently ensuring VERY slow and smooth panning/tilting will help avoid the judder for the most part.

I've spent a lot of time since posting this question watching a host of different videos filmed on DSLR's and the 'judder' is a lot more common that I had realised. In many cases though, unless you really look for it, your attention is so focussed on the subject/content of the video (as it should be!) that it doesn't detract from the story/experience in any major way.

Again, thank you for your help.


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