GH5 GH5 Moire

stoneinapond said:
Just watched the first clipagain on a 5K monitor but at the native size. The lampshade is full of moire. I do think the native lens has something to do with it.
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Really don't see anything here, the frequency is simly not high enough.
There are some slight hints of aliasing though, nothing to be worried about.

Wondering which sharpening setting was used. The higher, the more pronounced it will be...


If you want to watch it on a 1080p screen you'll always need to blur the footage before downscaling to prevent Moire.
 
stoneinapond said:
Just watched the first clipagain on a 5K monitor but at the native size. The lampshade is full of moire. I do think the native lens has something to do with it.
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So you downloaded the footage and then watched it on a viewer exactly the size of UHD and you got "full of moire"?
 
Thanks, Dingo, you did the same thing. The original image has no moire.

lamp.jpg

But downscaling it, to fit whatever resolution your screen happens to be, will result in phantom lines, unless you blur it, like DeeZiD says --- although I had better luck blurring it afterwards rather than before.

lamp-shrunk.jpg lamp-shrunk-blurred.jpg

That's because basically your lampshade is the same pattern as a resolution test chart :laugh:
 
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Maybe I need to change the lamp... But seriously I did'nt expect all these downscaling troubles. Cropping and rescaling everytime I have a problem (and I've seen moire and aliasing not only on the lamp) it's not what I was expecting from this camera. Maybe the GH5 is few years ahead and I am left behind, I don't know. Maybe I picked the wrong camera for my needs (but I still have my GH2...). Like I said I need to downscale my 4k footage in order to control the 1080 quality bfore sharing as I always done with my 4k Gh4 stuff. And, DeeZid, Sharpen always -5.
 
I have run into far less moire on the GH5 than I on the GH4. Granted, I have shot far more 4K footage on the GH5 than I ever did on the 4, but I would go so far as to say that moire has not been an issue for me at all! Recently, I shot this promo for a local realtor. I was very concerned when I saw his shirt and discovered his alternative clothing was the same small-patterned design. But, in both filming and post, I found no issues with moire, where I know the GH4 would have struggled. I shot this in 4K 24fps:
https://vimeo.com/230958962
password: hiddeninventory
 
Cary Knoop said:
Well, as you can see in the image above there is no moire in the original.
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We are not talking photos. This is a about moving images. Imported the footage into FCP X and went through it frame by frame. Yes, a single frame can look fine, but when there is a series of them, the picture changes (no pun intended).

So I'm not sure who is trying to convince who of what, but I see what I see, and that is the end of it as far as I'm concerned. Personally I don't have issues with moire, but that doesn't mean it can't exist.
 
stoneinapond said:
We are not talking photos. This is a about moving images. Imported the footage into FCP X and went through it frame by frame. Yes, a single frame can look fine, but when there is a series of them, the picture changes (no pun intended).
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Perhaps your video card cannot keep up or your refresh rates are incompatible?
 
stoneinapond said:
We are not talking photos. This is a about moving images.
Click to expand...

I'm using MAGIX Vegas Pro 14 running under Windows 10, and I am not seeing ANY moire in either the 4K still image or the 4K video during playback.

In both cases the 4K lamp image is completely clean when viewed at 1:1 pixel size. So to me this does NOT appear to be a camera issue, but rather a downscaling issue because of the patterns on this lamp, and it appears this problem can be controlled by adding some blur to the lamp image.

I am pretty sure you would experience the same downscaling issue with any video camera that can capture a clean 4K image of this lamp.

What I am curious about is: What does GH5 1080p footage look like ? Does the camera do a better job downscaling than post software ?
 
TheDingo said:
I'm using MAGIX Vegas Pro 14 running under Windows 10, and I am not seeing ANY moire in either the 4K still image or the 4K video during playback.
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Very strange.

But to answer Gary's comment, if that were the case (my computer) then logic would demand that out of the tens of hours of footage I've shot, I'd see at least one case of moire. And as I stated in my first reply, i have never seen anything remotely like this, or even a hint

So it's a mystery to me as to why some would see it in this instance, and others not.

Hopefully the OP can find a solution that meets his needs.
 
OK everybody, thanks a lot for the help. I think I can live with this (great) camera anyway. Maybe the pattern on my lamp is a bit extreme. In future I'll avoid to point my GH5 on this wonderfully designed object.
 
Francesco Dal Bosco said:
In future I'll avoid to point my GH5 on this wonderfully designed object.
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Usually you can eliminate moire by either moving closer or farther from the thing that is causing the moire, or by changing the focal length of the lens you are shooting with. The only way to be sure while shooting is to have a monitor that can display a 1:1 pixel image from your camera, so you can then make adjustments on the fly to get rid of the moire. I used to do this all the time when I shot with the GH3 because people's business jackets often have a weave that can moire with the wrong set-up. ( I once had to re-do an interview shoot for free because of the wonderful moire that kept popping up in post )
 
Conclusion:

Not a GH5 problem. The GH5 is actually on of the least problematic cameras available in terms of aliasing and moire.
The problem appears when clean 4k footage with high frequency detail is being downscaled for lower than UHD screens.

Solution:
Buy a new screen/TV
or
Blur before downsample
or
(Try) Diffusion filters
or
Change the lamp or make sure it's not in focus or change the distance/focal length to make the pattern bigger or smaller.
 
DeeZiD said:
Conclusion:

Not a GH5 problem. The GH5 is actually on of the least problematic cameras available in terms of aliasing and moire.
The problem appears when clean 4k footage with high frequency detail is being downscaled for lower than UHD screens.
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Yes, it's because the aliasing artifacts are always there, blended together with genuine image details. Moire patterns occur when the image is scaled to a ratio that resonates with spatially inverted aliasing patterns, reflected across the Nyquist wavelength of the image sensor. Slightly blurring the image before scaling can reduce the edge resonance without excessively degrading the underlying details. It's similar to how a focus peaking display can suddenly get supersharp at the precise point of focus.
 
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Thomas Smet said:
Another option is to add a filter to the front of the lens to slightly soften the details and mimic a low pass filter. Not the same thing but it might be enough in your situation.

Yes it is a bummer but its the reality of shooting with hybrid cameras that need more pixels for stills. If it was up to me I would have preferred the GH5 with less pixels so it had just enough for 4k video which could have slightly helped the sensitivity and dynamic range. Alas I doubt we will ever get such a thing so unless we move to a dedicated video/cinema camera it is what it is. You either have crop or a less than optimal method of scaling. I had hoped the method of scaling on the GH5 would be enough to combat moire but it is starting to sound like that may not always be true.

The lens choice may affect the potential for moire as well. The sharper and more detailed the image the more high frequency detail can freak out.
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You're right. I guess the workaround is always going with -5 as default setting for sharpness. I've also noticed if you add blur on Pot Player as for instance, you'll be able to diminish or even totally overcome the issue.
 
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