Strange aliasing on C300

J

Joe Media

Active member
We just bought a C300 PL and so far, completely love the image it produces. I'm not totally familiar with the camera yet so hopefully this is just a sharpening or playback issue. We were on a shoot today doing some talking head interviews and everything looked great through the LCD and EVF. Just got back to the studio and are now seeing tons of moire Namely on some fine pattern jackets and ties. The strange thing is that it's only through our preview monitor out. If I render it to a file and playback on the computer screen, there's no moire. It's just through the SDI out to the preview monitor. I've never seen this before. On all other source files (R3d's, AVCHD or other) there has never been moire. We're using the Able Cine JR Cine color profile. Any ideas? There's no finging or aliasing, just moire on the fine patterns (much like the original fine pattern footage from the 5D). I've run it through Premiere and Vegas and both show the same moire (it's 23.976 1080p) Any ideas? If I render it out to a uncompressed file and put it back on the timeline, there's aliasing to the SDI monitor. If I play that same file on through the computer monitor, no moire. I'm stumped.
 
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If there's no aliasing on the computer screen, then it appears because the preview monitor (or something in between) deinterlaces the image.
 
Hmmm,
c300-aliased-fringe-not-so-awesome
scarlet-vs-C300.jpg
c300-aliased-fringe-not-so-awesome

http://www.nextwavedv.com/c300-aliased-fringe-not-so-awesome/
 
Thanks for the insight guys. The preview monitor as well as the preview in the editor is scaled to 100%. I took a screenshot of the preview monitor and exported a still for comparison. It's so strange that the still extract shows no moire but the preview screen does. I shot an interview on our Epic last week and the interviewee was wearing a herringbone jacket with a high contrast pattern and no moire. I'm stumped. We do a lot of broadcast and I've always trusted this monitor...what you see is always what you got. I just can't figure out where the moire is coming from. Ideas?Image1.jpgphoto.jpg
 
I had this same issue once with a 1080p field monitor once. I don't remember the make or model, unfortunately (it was a while ago), but it did cause a bit of a panic until we saw the video at full scale on an Apple Cinema Display. There was no moire in the shot, but for some reason it showed up on this one particular monitor. Ultimately, we just trusted what the Apple monitor showed us and never had a problem in the final delivery.
 
I tested some footages from C300 and got the same result, on PC monitor it is ok, on TV (Panasonic plasma) after export there is moire on the fine details. I believe to this because I tested a lot of footages on this TV from many types of cameras (as a standart way of the distribution). Every camera can makes some moare, sometimes less or sometimes more visible, C300 looks as the one with more visible moare on TV screen. Yes I saw this.

Picture from the P.B. films on TV in attachment.
 

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This is an interesting idea, and with detail turned all the way down to -10, you'll likely see better performance. I've read from AbleCine's blog that using the Cinema Lock mode on the C300 "does add some very limited sharpness (detail) to the image," and they advise using the CINEMA custom preset instead to ensure that you have all sharpness turned off. (source: http://blog.abelcine.com/2012/03/23/canon-c300-scene-files-from-abelcine/)

In the one project that I experienced this issue, I had used Cinema Lock, so that could very well be the culprit. I've always used a CP setting since (CINEMA, TRUlog, or EOSlog) and have been completely moire free since. All of those custom log profiles have sharpness at -10.

Although, does it explain why the moire exhibits on a television monitor, but not in the native footage viewed full-res on a computer monitor?
 
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I get this issue all the time. Let me rephrase that for you. I see this non issue often.

For the most part Im shooting in CP's using Canon Log with sharpness turned down so, as a base Im talking about Canon Log with sharpness turned down.

When I see moire.

1/ Often on the cameras LCD or EVF.
2/ When Im looking at an image on my 58" plasma thats not moving i.e. the playhead in my timeline is still.
3/ On a broadcast monitor again when the playhead is still.

Only happens on very fine detail.

The issue - well the LCD and EVF side is easy - they cant resolve what the camera is. And when the image is still neither can my plasma.

I get the same issue if I drag in a very high res high detail still photo from something like the 5dmkII with sharp glass. I get the same issue with Red footage downscaled to 1080 if theres a lot of fine detail.

When I dont get it - watching images from the C300 on my 30" Apple display with the resolution set to max. Probably due to the fact that my original is being stretched out so the lines are pulled apart a little more to where they naturally should be sitting. I also dont get it when Ive exported a still from the timeline.

EDIT TO ADD: I shot some footage at a University about a month or two after I got the C300. Sandstone buildings many had like air con vents and in my wides, on my LCD and EVF I thought I had a huge problem as I could see so much moire. Back in edit - nothing apart from what I say above.
 
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