AC130: Ac130 aliasing

J

Jglenn

Member
I just finished a video where a couple of the performers wore either a striped sh
irt or pants. I saw that the stripes were waving around but have no clue as to how to either correct it or prevent it from happening. Is there a setting on the ac130 that I am overlooking to prevent this or a way to correct it in post? I am using Vegas 1pro as an editor. I was shooting in 720 60p. Would shooting in 30p vs 60p help or make matters worse?
 
Did you see this when viewing at 100% size in Vegas? Sometimes moire appears in camera when the camera downscales for the LCD but the actual footage is fine. I've had no problems in 1080p.
 
It was there in Vegas at 100% and happened when zoomed in about 3/4 of the way. Do you think it's better to tape in 30p or 60p?
 
I assumed you were talking about moire resulting from the cameras resolution limit, but if its more if a problem at longer end of the zoom, perhaps you're describing the "rolling shutter" effect that all CMOS and MOS cameras display to some extent. Could you could post a short clip?
 
Image2.jpg Thanks Nate. I was unable to get a video clip to upload as an attachment but I have an extact photo so I hope that will suffice to see the effect I'm getting. I'm new to the HD field and didn't have the problem with my GL-2's.
 
Ok, I think I was right. What you're seeing are Moire patterns because the sensor can't resolve the tiny patterns in the clothes. Frame rate shouldn't matter, but recording in 1080p could definitely help as the camera is designed to shoot in that mode versus 720p. Theoretically more resolution would result in more detail and less moire. You may also try turning down your sharpness settings in the profile.

A way to re-create the problem would to test shoot anything with really fine detail, like fabric or carpet then move the camera slightly to see if the moire patterns appear. It may help to attach the camera to a 1080p monitor/TV via HDMI so you can really see what's going on.
 
Thanks for the help Nate. I'll do some tests and see if I can work it out. I wasn't really sure what I was seeing so this really helps.
 
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