Help! Reducing red-bleeding in Camera

A

andybiz_2005

Well-known member
I recently shot a concert last week & they had all kinds of stage lighting. There were white lights, then blue lights, then green lights & finally red lights shining on the actors on the stage. I noticed that when the red lights where shining on the subjects, everything began to color bleed red & it was very obvious.

I know that miniDV cameras are not good at rendering subjects when a red light is shone on them. Do high-def cameras like the Sony FX1 or Sony Z1p suffer from this same color bleed when red light is shone on subjects?

Is there anyway that I can white-balance, or adjust the in-camera settings to reduce the red color bleeding in future concert shoots? Are there hardware filters specially designed to mount on the camera lens to reduce the red bleeding effect like a polarizer reduces reflections & glare?

When I deliver the DVD to my clients, I may have to tell them that the red bleeding on subjects couldn't be avoided because of the limitations of my camera & the lighting on the stage. Is it wise to explain it to them this way, that it was beyond my control, but I tried my level best to get the best image possible from my camera.

Would the RedOne camera suffer from this red bleeding effect, or is it too high-end for this? Thanks very much in advance.

Andrew
 
andybiz_2005 said:
I know that miniDV cameras are not good at rendering subjects when a red light is shone on them. Do high-def cameras like the Sony FX1 or Sony Z1p suffer from this same color bleed when red light is shone on subjects?
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Yes, because they have the same low chroma sampling (1/4 chroma sampling, 4:2:0 vs. 4:1:1 but it adds up the same). Further complicating matters is when they change colors HDV might choke on the fact that every pixel on the screen is changing whenever they raise or lower the brightness on those lights.

The problem you ran into is 4:1:1 color sampling (or 4:2:0) and shooting a solid-color object. That's a worst-case nightmare scenario for these low-color-sampling cameras. There's just not that much information recorded; these cameras only record color at 1/4 the resolution (so in a DVX you're not looking at 720x480 in red, you're looking at 160x480! That's why it's low-rez and blocky.)

Is there anyway that I can white-balance, or adjust the in-camera settings to reduce the red color bleeding in future concert shoots?
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Well, the main thing would be to ask the house if they could just not do a red wash on the subjects. I doubt you'll get cooperation, but that would help.

You might be able to overcome some of it by using an off-kilter white balance, but I doubt it; the problem is they're shining primary colors at the subject, and primary colors like red & blue are going to mean 1/4 color resolution.

And it gets worse -- if you're shooting NTSC you're getting 4:1:1 color, and then when you author to DVD it's going to chop it in half again when it renders out at 4:2:0.

The best way to solve this is to use a camera that records more color info, such as an HVX in DVCPRO50.

The next-best way would be to get them to stop using red lights (or pure red lights) on the subject.


Would the RedOne camera suffer from this red bleeding effect, or is it too high-end for this? Thanks very much in advance.
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Red One would not suffer from this. DVCPRO50 or Digital Betacam or Digital-S/D-9, or MPEG-IMX would all overcome this.
 
Thank you very Barry for that excellent reply. It really cleared up my doubts. I'm using a DVX100A (PAL version). What do you mean by "off-kilter white balance"? Never heard of that term b4. Thanks again :)

Andrew
 
I mean white balancing so that red doesn't come into the camera as pure red. Maybe white-balance off a red card, so that it thinks red is white, and thus encodes red with the full luminance resolution instead of just the red portion? Although that's really going to compromise other aspects of the recording.

Obviously you'd have to color-correct in post to un-do the effect of the off-kilter white balance. And when you go to DVD you're still going to suffer from 4:2:0 color decimation, so it's still going to be less than optimal.

I'm just talking off the top of my head here, I have no idea if this will work.

And definitely do what HorseFilms suggests, try the chroma blur, I've seen it clean up red jaggies very nicely before!
 
Andrew,

If you take a close look at your captured footage, you'll likely also find bleeding/blockiness if they did a pure blue lighting as well. The red usually jumps out at you, though.

In post, you can use Magic Bullet Deartifacting to regain some definition in the reds. It's a worthwhile step if you are going out to DVD. DVD also loses some color definition, but it will look better if you get some back through deartifacting before you lose some to DVD.

One final tip would be to work in as close as possible on your shots. If you're framed nice and tight with close-ups, then the red bleeding will be less noticable. On a wide shot, it'll stick out like a sore thumb.

Josh
 
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