Serious Moire and Shimmer at 108050p
2205 11 2017-1-18
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griff2
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Just did a test shoot with the Mavic in D-Log.  Apart from the annoying over-sharpening which the default profile gives there's some serious moire and shimmer, I must admit I haven't seen this on anyone else's footage.  Thoughts:



2017-1-18
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Danny-B-
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Flight distance : 306640 ft
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Limitation of the sensor, 1080p at higher than 30fps isnt very useable i'm afriad ... shoot in 2.7 or 4k 30fps
2017-1-18
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Gallacherboy
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I have the same issue but I am shooting at 4K at 30 frames a second, also have a lot of grain in the images, shooting clear skies with the sun blaring, have to stop down on exposure, has your issue been resolved?
2017-1-21
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griff2
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I've been doing a lot of experimenting with the colour profiles and resolutions.  Shooting at 4k at 25p removes the shimmer and most of the moire.  Shooting in D-Cinelike (-1,0,-1) instead of D-Log gets rid of the digital noise.  D-Log seems almost unusable due to the digital noise which is a shame as I like shooting log and am used to grading this in Davinci for my A7ii.

Here I'm using D-Cinelike (0,0,0) it's slightly over-sharp and over saturated, hence I'm now going to use (-1,0,-1):

2017-1-22
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Somican
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Flight distance : 485997 ft
Germany
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Hi,

the video in your first post was filmed at 1080p/50hz right?

its a limitation in the method how the mavic used to capture 1080p48/50/60/96Hz. It causes aliasing and generally pixelated images.

Filming at 30hz its the only way to avoid the aliaising.

if u need more information look here







2017-1-22
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griff2
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Somican Posted at 2017-1-22 12:34
Hi,

the video in your first post was filmed at 1080p/50hz right?

Surely aliasing is not a function of time, but of resolution - at least for imagery.  I can see why moire might dissapear as the image resolution is altered.  The shimmer dissapeared as the framerate was was reduced.  So, basically 50/60p would be unusable.  I suspect the shimmer was due to a resonance effect on the gimbal, but would need to confirm that by experimentation - something I don't have time to do atm.
2017-1-22
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DRONE-flies-YOU
Second Officer
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griff2 Posted at 2017-1-22 14:31
Surely aliasing is not a function of time, but of resolution - at least for imagery.  I can see why moire might dissapear as the image resolution is altered.  The shimmer dissapeared as the framerate was was reduced.  So, basically 50/60p would be unusable.  I suspect the shimmer was due to a resonance effect on the gimbal, but would need to confirm that by experimentation - something I don't have time to do atm.

The sensor BINS at higher than 30fps.
2017-1-22
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JasonMBryant
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griff2 Posted at 2017-1-22 14:31
Surely aliasing is not a function of time, but of resolution - at least for imagery.  I can see why moire might dissapear as the image resolution is altered.  The shimmer dissapeared as the framerate was was reduced.  So, basically 50/60p would be unusable.  I suspect the shimmer was due to a resonance effect on the gimbal, but would need to confirm that by experimentation - something I don't have time to do atm.

The problem is bitrate. If only a certain amount of information can be recorded each second, then twice as many frames per second means less data per frame.

I also did a lot of testing a couple of days ago. Sharpness definitely needs to be reduced. I'm trying to decide if I want sharpness at -1 or -2.
2017-1-22
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griff2
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JasonMBryant Posted at 2017-1-22 15:04
The problem is bitrate. If only a certain amount of information can be recorded each second, then twice as many frames per second means less data per frame.

I also did a lot of testing a couple of days ago. Sharpness definitely needs to be reduced. I'm trying to decide if I want sharpness at -1 or -2.

Yes but assuming the same bitrate 1080 50p should still look better than 4k 25p since 4k 25p is four times the spatial resolution and half the temporal resolution of 1080 50p.
2017-1-23
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griff2
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DRONE-flies-YOU Posted at 2017-1-22 14:48
The sensor BINS at higher than 30fps.

Yes, thanks, just waded through all the linked info, now I understand what pixel binning is; interesting.
2017-1-23
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griff2
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JasonMBryant Posted at 2017-1-22 15:04
The problem is bitrate. If only a certain amount of information can be recorded each second, then twice as many frames per second means less data per frame.

I also did a lot of testing a couple of days ago. Sharpness definitely needs to be reduced. I'm trying to decide if I want sharpness at -1 or -2.

Also, sharpness wise I found -2 to be too soft and 0 to be over-sharp, so -1 it was for sharpness.  For colour saturation I did some tests using an "x-rite colorchecker video" in conjunction with Davinci using the Vectroscope and found -1 for saturation to be on the nail (after a bit of tweaking the sat and hue colour curves).
2017-1-23
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JasonMBryant
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griff2 Posted at 2017-1-23 11:50
Also, sharpness wise I found -2 to be too soft and 0 to be over-sharp, so -1 it was for sharpness.  For colour saturation I did some tests using an "x-rite colorchecker video" in conjunction with Davinci using the Vectroscope and found -1 for saturation to be on the nail (after a bit of tweaking the sat and hue colour curves).

Yeah, -2 makes the background look a little better, but then my face or anything else that I want detailed isn't sharp enough. Davinci Resolve allows you to select an object and track it as it moves through a scene. I think sometimes I might shoot in -2 and then just track and sharpen the things that need to be sharp.
2017-1-23
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