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-   -   Partial Frame Camera Flash Artifacts (https://www.dvinfo.net/forum/canon-eos-full-frame-hd/487610-partial-frame-camera-flash-artifacts.html)

Todd Sheridan November 17th, 2010 08:39 AM

Partial Frame Camera Flash Artifacts
 
Just looking at some footage I shot from the recent NYC Halloween parade. It looks pretty nice, except that the hundreds of cameras (with flash) being constantly used has filled almost all of my footage with weird partial frame "artifacts" every time a flash bulb goes off.

I (mostly) understand this is a result of the rolling shutter, but was wondering if there was possibly anything that could be done in post to correct this issue?
I'm assuming there probably isn't, besides actually removing frames (which I may try, and see which looks worse).

Also wondering if there is anything that can be done in the future to avoid this?

Thanks in advance, and I apologize if this has been discussed elsewhere in the past.

Chris Medico November 17th, 2010 08:49 AM

The only real thing you can do to avoid it is to use a CCD camera. That is a common artifact with CMOS cameras.

Instead of deleting the frame replace it with a white frame or duplicate the previous frame and place a white mask over it with a bit of transparency. That looks the most natural of the things I've done to correct it.

That effect bothers me but has never been mentioned by a customer. I even see it on local news now they have also gone to CMOS cameras. No one seems to give it a second thought.

Todd Sheridan November 17th, 2010 09:32 AM

thanks
 
thanks, i'll try playing around with some frame replacement, etc.

i don't necessarily think the footage is totally ruined. if this were for a wedding, etc. i would give the footage to the client and probably feel ok about it.
but, i was hoping to use it for my reel, and wondering if it's a deal breaker.

Ken Diewert November 18th, 2010 04:32 PM

Todd, I did have a wedding shoot that was full of flashes especially during the first dance, and I painstakingly pulled almost all of the frames- I just wanted to try it to see how much work it would be versus the difference in the look. And the truth was, it depended... sometimes the action was a little to jumpy with the missing frames and sometimes it was (virtually) seamless with the missing frames. But all in all, I think it was better with the frames pulled, though Chris' idea may look better though seems like a lot more work.

Nigel Barker November 20th, 2010 05:14 AM

I don't know if this would help with your case but there is Flash Removal plugin in the NewBlueFX Video Essentials package that is claimed to remove camera flashes NewBlue Video Essentials | Video effects plugins for Avid Liquid, Avid Media Composer, Adobe Premiere, Adobe After Effects, Apple Final Cut Pro, Apple Motion, Corel VideoStudio, Pinnacle Studio, Sony Vegas, Canopus Edius and other video editors.. This before & After demo footage looks very impressive

The package s only $79.95 & there is a fully functional free trial so it must be worth a try.

Greg Fiske November 23rd, 2010 11:49 AM

http://www.dvinfo.net/forum/newbluef...a-flashes.html

Todd Sheridan December 16th, 2010 12:55 PM

here is the clip in question:


as you can see, there are a lot of flashes, and to me it's rather distracting (although others i've spoken to don't seem to mind it)

I installed the NewBlue Video Essentials package and tried the trial version of 'flash remover' plug in, but as far as I can tell, it made zero difference whatsoever.
Not sure why this is, as the sample clips definitely seem impressive, and i've heard of it working for people.
(also strange is that it says it will include a watermark since i am using the trial version, but after applying the filter and rendering, i not only see no difference, but also see no watermark).
Anyway, I'll keep playing with it, I guess.

Andrew Waite December 18th, 2010 01:33 AM

I too have not had success with NewBlueFX's flash removal with dslr footage. I'm sure the rolling shutter complicates things.

Erik Andersen December 18th, 2010 09:28 AM

i really think this is just part of the "look" of these CMOS-chipped cameras. I've always liked them really.

Removing or "fixing" these flashes does not look natural. Most of the tricks attempted to "fix" footage just take away the immediacy and authenticity.

Like all the other flaws of the 5D, you need to... embrace it!

Walter Brokx December 18th, 2010 11:14 AM

Only flashes in 'front' of the camera that fill a large part of the frame seem a little distracting, because they are partial, the flashes in the background aren't distracting: they don't fill the width of the screen.
So if you want to fix this, I suggest adding the rest of the flash to the image. Since a flash is only 1 frame, you will probably get away with not very precise fixes.

Cool shots, btw...

Last easter I made this:
YouTube - Paas_English.mov

I used a speedlite to fake gunfire and the rolling shutter produced some partial flashes.
I shot 60 frames per second at 1/60 (on a Sony EX1R), so when a flash was 'broken', it continued on the next frame. In After Effects I fixed it, but you could use Photoshop as well. But shooting 30 fps at 1/30 or 25 fps at 1/25 is a bad idea, since it will cause too much motion blur.


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