View Full Version : Zebra Lines...
I filmed an interview with a patio screen in the background with an HV20. The problem is there are black and white lines like zebra lines on the patio screen in FCE. It does not look very good at all. Any suggestions to tone down the wavy lines?
mikkowilson
08-06-2007, 12:25 AM
The effect you are seeing is called "Moire", it comes from the positive and negative interfearance between the pixels in the sensor, and the holes in the screen.
A slight blur should help remove it, but you will probabaly want to mask the blur so that it only effects the screen if possible.
- Mikko
Thank you for your explanation and suggestion. I did actually try a "soft effect" a few days ago and it did take away the interference. I know for next time not to shoot in front of a patio screen!!
AuditoryVisuals
08-09-2007, 05:51 AM
http://en.wikipedia.org/wiki/Moire
It's got a lot of info their.
And if it's chromatic, a 3 sensor camera should take care of that. Like an XH A1.
Erik Olson
08-09-2007, 06:23 AM
You can get moire in Venetian blinds, coarse textiles and horizontal cloth patterns as well. Things to avoid whenever possible.
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In FCP6 is there a way to select just the screen in the background as a blur, or do you have to blur the whole image?
Just wondering how you can mask a slight blur in FCP6. I think I can slightly blur the background screen, but do not want to blur the main actress in the shot. Do you know how to blur the image in the background, but mask the blur on the actress in FCP6? Will I have to take this footage to a pro for touch-ups?
Thank you,
Rory
There is a relatively easy (but not perfect) way to do this if your actress is not moving too much.
Place a duplicate of your footage on V2 (this will become the footage of the actress).
Place a filter on the V2 footage called Four-Point Garbage matte.
Turn off video monitoring for V1 (this will help with the next step)
Go into the filter settings for the v2 clip. You should see the settings for your garbage matte.
Click point 1 and drag the crosshairs close to your actress (not too close, leave some space around her).
Repeat this step with the other three points. You should now have your actress alone on a black background.
Increase the Feather setting on the garbage matte filter to soften the edge.
Turn video monitoring on v2 off - and turn v1 ON.
Add a blur to the clip on v1. Pick Guassian and set it to 20 for starters to really see the effect then lower it as needed later on.
Turn on video monitoring for V2.
Your actress should be in focus on a blurred background.
For further tweaking....do the same thing with an 8-point matte instead to get a better cutout.
Hope this helps.