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Canon 5D: weird brightness flicker

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Andy Taplin
Canon 5D: weird brightness flicker
on Dec 1, 2010 at 6:03:02 pm

Hi All

I shot an interview with the 5D and there is a random brightness/gamma change on about 50% of 45 minutes of the footage. Fortunately I was also shooting with a PMW350 which is clean so I'm OK but I'd like to work out what the issue is here for the future.

I'm assuming it's not a hardware fault but can't work out what else it could be. My settings were as follows:
1920x1080 25P
Manual exposure 50th/sec shutter f/4
ISO 160
sharpness 0
contrast -4
saturation 0

Here's a link to a short QT movie showing the problem. It's really obvious if you scroll quickly through the clip: 1341_5dbrightnessflicker.mov.zip

Any thoughts?


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Phil Balsdon
Re: Canon 5D: weird brightness flicker
on Dec 1, 2010 at 8:25:44 pm

Sample in link looks stable to me.

Cinematographer, Steadicam Operator, Final Cut Pro Post Production.
http://www.steadi-onfilms.com.au/


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Peter Burger
Re: Canon 5D: weird brightness flicker
on Dec 1, 2010 at 8:54:10 pm

I could spot a brightness change on the wall in the back. I would assume it's the changing brightness from outside the window.
But that should be on the footage of the PWM as well... So, indeed very strange...


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Andy Taplin
Re: Canon 5D: weird brightness flicker
on Dec 2, 2010 at 12:27:42 pm

It's definitely not the light changing as it's only on the 5D footage. You can see the levels change on the whole image, although it's much more noticeable on the BG.

I assume in manual mode there are no 'gotchas' where there is still some auto exposure compensation going on?


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Peter Burger
Re: Canon 5D: weird brightness flicker
on Dec 2, 2010 at 12:58:24 pm

Did you set the "highlight tone priority" and "auto lightning optimizer" to off? In some cases they produce strange artifacts - at least on my T2i and the 7D.


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Andy Taplin
Re: Canon 5D: weird brightness flicker
on Dec 2, 2010 at 1:20:28 pm

Auto Lighting Optimiser was set to standard, so maybe that was it. I'll try some tests

Thanks for the replies


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Chris Wright
Re: Canon 5D: weird brightness flicker
on Dec 5, 2010 at 11:13:04 pm

also, just to see if I could fix your footage, I made a quick auto fix after effects project. it auto fixed your white balance and flickering exposure.

ae cs3 aep
http://www.mediafire.com/?snyc3empeaea2bk

a gui script for enabling expressions(if you scrub, sometimes they get disabled)
http://www.redefinery.com/ae/view.php?item=rd_ExprTweaker

http://technicolorsoftware.hostzi.com/


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Andy Taplin
Re: Canon 5D: weird brightness flicker
on Dec 6, 2010 at 11:17:42 am

Thanks Chris that 's really good of you :-) I've tried the AFX effect in the past that's supposed to even out exposure without much success.


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David Williamson
Re: Canon 5D: weird brightness flicker
on Jun 10, 2011 at 8:33:08 am

Any chance you could re-post that auto-exposure fixing AE project? I've run into the same issue with exposure flickering...


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Chris Wright
Re: Canon 5D: weird brightness flicker
on Jun 10, 2011 at 8:58:27 pm

http://www.mediafire.com/?fz0s3i85a45ou58
from thread
http://forums.creativecow.net/thread/50/857931#857958

if you un-hide the final output comp, and enable the top empty text layer, it will show numbers in your comp. If it says around 25 (+-5 deviation) from gamma clamp slider, the flicker will be removed automatically.

it may need a new keyframe for a new scene to scene change, but for the most part, it's fully automatic. obviously before you render, turn the text layer off.



also, if you're interested, I made a highlight restore program that recovers blown out spots in video >2x adobe's RAW capability too.
http://www.mediafire.com/?o5724wvxd07mkv7
from thread
http://forums.creativecow.net/thread/2/978546#978880

http://technicolorsoftware.hostzi.com/


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Dean Barker
Re: Canon 5D: weird brightness flicker
on Nov 24, 2011 at 5:35:48 am

can you tell me how to apply your auto fix filter? - i'm very green with after effects so explain it like you would to a newbie - thanks!


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Jared Levy
Re: Canon 5D: weird brightness flicker
on Aug 15, 2012 at 3:02:43 pm

Hey Chris,

I am experiencing similar issues with interview footage shot with the 5D. The background was a solid grey and it is causing very strange gamma shifts whenever our interviewee moves within the frame. Needless to say, I've never seen anything like this before. I'm well versed with the 5D2 having owned it since it came out.

My team and I have been forum hopping looking for solutions and came across your AE links. As your posts are a year old those links are dead. We were wondering if we could discuss our issue further with you and perhaps see what AE solutions you may already have for it. Thanks a lot, your help and time are greatly appreciated.

Feel free to email directly if you wish: jared@alreadyalive.com


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Andy Taplin
Re: Canon 5D: weird brightness flicker
on Aug 15, 2012 at 3:25:48 pm

Jared

I'm jumping in here as I may have a solution for you. Boris Continuum Complete 8 has a flicker filter that should be able to remove it. Take a look at this link:

http://www.borisfx.com/videos/BCCAVX/Remove-Flicker.php

I think my original problem was caused by having the Highlight Auto Optimiser turned on in the menu as I've never had the issue again.

Andy

Andy Taplin
Director / Lighting Cameraman
http://www.peninsulafilms.com
http://www.andytaplin.co.uk


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Jared Levy
Re: Canon 5D: weird brightness flicker
on Aug 15, 2012 at 4:30:00 pm

Thanks Andy, appreciate the link. It definitely helps the issue. The filter does not alleviate the flicker completely but still a dramatic improvement. We certainly learned our lesson about Highlight Auto Optimiser. Disabled forever.

Best,
Jared


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Chris Wright
Re: Canon 5D: weird brightness flicker
on Aug 19, 2012 at 9:43:53 pm

I reposted the files to remove flicker. I haven't compared it to boris. Perhaps you can.

ae cs3 aep
http://www.mediafire.com/?5vkfg7ash7tgvj7


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