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    Canon 7D Moire meet the Dutch Angle
    #1
    Senior Member stephenvv's Avatar
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    Okay, just got a 7D couple of days ago and wanted a better handle on aliasing color moire issues. I found a perfect test to shoot and test my theory that angle is everything based on looking at Barry G's test charts.

    I think this test shows that long horizontal lines +- 10-15 degrees are the issue. Dutch the angle enough and it appears to my eyes that the effect vanishes and nothing but nicely sharp footage remains.

    Shot factory default, 1080 24p, very high shutter as I had no ND plus it keeps motion blur from hiding result. Download the WMV as compressed Vimeo is not 100% accurate of what moire I see on with camera directly in 1080p monitor.



    MOIRE IN FULL FORCE


    MOIRE GONE
    stephen v2
    "A film is - or should be - more like music than like fiction. It should be a progression of moods and feelings. The theme, what's behind the emotion, the meaning, all that comes later."
    Stanley Kubrick


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    #2
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    interesting!

    I guess now well see a thousand remakes of the THIRD MAN


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    #3
    Senior Member stephenvv's Avatar
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    Indeed - I"m lucky - my last name is Dutch - "van Vuuren", so I'm all set
    stephen v2
    "A film is - or should be - more like music than like fiction. It should be a progression of moods and feelings. The theme, what's behind the emotion, the meaning, all that comes later."
    Stanley Kubrick


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    #4
    Senior Member MovieSwede's Avatar
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    Handy in case you gonna make Battlefield Earth 2. ;)


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    #5
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    If you decide - Im shooting 720 - its all this cam is good for

    it does indeed ad another tool the the box

    Tram needs to write a 16:9 frameguide that rotates

    S


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    #6
    Senior Member Matthew Bennett's Avatar
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    Ha! Great test...
    I actually really like your test shot too... it has sort of a David Lynch in the suburbs feel...


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    #7
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    That's interesting. If you're making more tests, the Canon 7d has an 'artificial horizon' built in so you can see the forward and lateral tilt - maybe you can measure the exact angles. your theory certainly seems consistent with everything we know about how Canon bins pixels on their sensor.


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    #8
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    That could come in handy big time. Not optimal of course, but shooting off angle just enough to get rid of the Moire and the cropping and reorienting in post is one more workaround to consider if you just can't seem to get rid of the really nasty moire as shown here.


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    #9
    Senior Member stephenvv's Avatar
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    Eddy - good point. I don't have a laser level or anything to check that the ground is flat, but if someone does, the exact angle range of the effect which lessens by degree off true horizontal, could be determined.

    And I wonder if smart programmer people could use this data if the 7D records the angle in metadata to create a moire-removal plugin. It's clearly an effect that only regular people see when it's the moving moire on strong horizontal lines.
    stephen v2
    "A film is - or should be - more like music than like fiction. It should be a progression of moods and feelings. The theme, what's behind the emotion, the meaning, all that comes later."
    Stanley Kubrick


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    #10
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    It works. We were doing this with the MKii when everyone attempted to find out how to cure aliasing and if you're purposely framing just a tad wider you can crop out of the image enough to be able to tilt it in post BACK to a proper horizontal composition.

    It's easy if you're going to finish at 720 or anything smaller than 1080.

    However, the method does not work with various laterals in the frame: buildings, powerlines and vehicles for example. One surface may be cured, but the others become plagued.

    In Stephen's example, you can see the chairs on the deck are now jagged.
    Comet Color Page
    Allow me: fanboy of great images.



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