aliasing and moire?
- Thread starter jenningsp
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Dark Side of the Camera
I found aliasing in neon lights, but no visible moire.
Frank
Frank
David G. Smith
Steak Knife Member
I have ran across some moire while rack focusing through a window with a fine screen on it. Once the focus point changed either inside or outside of the window it went away.
speedracerlo
Well-known member
Is there a difference between aliasing and moire? I have run across some of this stuff while focusing onto my computer speaker's finely patterned outer screen cover
David G. Smith
Steak Knife Member
Barry Green's article is one of the best explaining the aliasiing.
http://www.dvxuser.com/articles/article.php/20
Moire is also an issue with imaging systems and is usually seen as a multiple color artifact over fine detailed patterns.
http://en.wikipedia.org/wiki/Moiré_pattern
http://www.dvxuser.com/articles/article.php/20
Moire is also an issue with imaging systems and is usually seen as a multiple color artifact over fine detailed patterns.
http://en.wikipedia.org/wiki/Moiré_pattern
speedracerlo
Well-known member
Thanks for that article David, thats a lot of info on aliasing
NeedCreative
Well-known member
You're at risk got getting aliasing or moire on most sensors using a Bayer filter. But the fs100 and similar cameras show much less compared to DSLRs, so much less that, again comparatively speaking vs DSLRs in video mode especially Nikon and Canon, it's virtually none.
Edit: I want to qualify that I haven't seen moire patterns on the Fs100 at all, even with demanding footage such as distant brick, house siding, skyscrapers all in focus, etc. I've seen very minor fleeting aliasing that didn't look noticeable or unpleasant as noted Barry's article.
Edit: I want to qualify that I haven't seen moire patterns on the Fs100 at all, even with demanding footage such as distant brick, house siding, skyscrapers all in focus, etc. I've seen very minor fleeting aliasing that didn't look noticeable or unpleasant as noted Barry's article.
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Me and my friend shot some landscape stuff from his NY apartment (skyscrapers and other buildings.) He used his 5D, I used my FS100.
The 5D footage had so much moiré on every brick wall that it would be unusable for anything other than web/YouTube stuff or maybe (?) static images in narrative work. But then the camera has to be dead still. Panning over the lower manhattan skyline was horrible... Our eyes instantly locked onto the hypnotizing and moving moiré patterns. They catch all your attention instantly when panning.
The FS100 had no moiré what so ever. Day and night compared to the 5D.
I haven't done any aliasing tests yet though.
The 5D footage had so much moiré on every brick wall that it would be unusable for anything other than web/YouTube stuff or maybe (?) static images in narrative work. But then the camera has to be dead still. Panning over the lower manhattan skyline was horrible... Our eyes instantly locked onto the hypnotizing and moving moiré patterns. They catch all your attention instantly when panning.
The FS100 had no moiré what so ever. Day and night compared to the 5D.
I haven't done any aliasing tests yet though.
NeedCreative
Well-known member
The lack of aliasing and especially moire is what drove me ultimately to the FS100. It was a deal breaker for me on the 5D2, T2i, 7D, etc. Hate it.
NeedCreative
Well-known member
Water was another place the DSLRs blew it consistently. I remember killing myself for a shot on the beach at sunset running down with a Glidecam, to get home and see all kinds of aliasing and rainbowing on the horizon where the water met the sky. I was SO annoyed. Never again
David G. Smith
Steak Knife Member
I ran into some more issues with moire on my FS100 again due to window screens today. Other then that, the camera is so much better than a DSLR on that.
NeedCreative
Well-known member
As with all video cameras, one still has to be mindful of certain patterns that can cause moire. It's just thankfully far more rare in these cameras (i.e, like most other video cameras) than with the DSLRs which were, frankly, horrific in this area. Line skipping + an AA filter designed for stills = nightmare
Rick Burnett
Section Moderator
I've seen the Red One moire on window screens as well, not an easy thing to film.
I'm also getting ready to post an aliasing test on here with 7D, FS100 and AF100.
I'm also getting ready to post an aliasing test on here with 7D, FS100 and AF100.
The only moire I have seen from RED material has always been caused by demosaicing to HD resolutions with a too fast algorithm. The original 4k files have no moire to speak of. I would bet that the window screens were completely clean in the original 4k size.
morgan_moore
Major Contributor
Im happy
7d
Big files : http://dslr4real.tv/index.php?option=com_zoo&task=item&item_id=80&Itemid=1
S
7d
Big files : http://dslr4real.tv/index.php?option=com_zoo&task=item&item_id=80&Itemid=1
S
3-chip cameras also exhibit aliasing and moire under certain conditions. Any digital camera with a fixed pattern of pixels will show aliasing at some resolution. Moire occurs when the fixed pixel pattern interacts with other patterns in the field of view that are near the same spatial frequency as the sensor. Video cameras are designed to minimize aliasing and moire effects via optical low pass filters in front of the sensor that filter out high frequency details that can cause the problem. This is because the artifacts are much more objectionable in moving images. Video from DSLR's exhibit more aliasing and moire because they are optically optimized for full resolution stills, not HD video, and the resolution subsampling for video adds to the problem if not done well.
Rick Burnett
Section Moderator
Nope, I looked at the original 4K file 1:1 and saw the moire there. It was red and blue chroma moire all across the screen. In addition, high spatial differences like the colors on chrome also produce aliasing on the RED when viewed 1:1. When reduced to 1080p the aliasing on the chrome goes away and the image is absolutely amazing. The colored moire however does not go away. That is the ONLY condition I've seen colored moire on the RED. Mesh screens of course are the absolute worst thing to try and film given the fine repetitive detail.
Maybe the demosaicing was at half quality?
I just bought the german video magazine "Videoaktiv Digital" and they meassure the vertical resolution at 671 line pairs (horizontal 660 lp)
Isn´t that a little low (below 720p) ? They also write the F3 resolves over 300 lp more!
Edit: Jesus! A few pages further they test the new Canon Legria consumer camcorders. The resolve 794 and 960 line pairs....For 750 and 900 Euros...
The Canon 600 D was measured at 704 lp vertically. More than the FS100 ?! This can´t be right!
Isn´t that a little low (below 720p) ? They also write the F3 resolves over 300 lp more!
Edit: Jesus! A few pages further they test the new Canon Legria consumer camcorders. The resolve 794 and 960 line pairs....For 750 and 900 Euros...
The Canon 600 D was measured at 704 lp vertically. More than the FS100 ?! This can´t be right!
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