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"Dirty screen syndrome" when panning G7

Discussion in 'Panasonic Cameras' started by Duke Sweden, Aug 9, 2016.

  1. Duke Sweden

    Duke Sweden Mu-43 Regular

    66
    Aug 9, 2016
    Duke Sweden
    Greetings from a new G7 user.
    I've noticed that when I have my G7 on my steadicam, or when I'm panning on a tripod, I get a "dirty screen" effect that is usually attributed to less than top quality monitors, but I get the same pattern no matter which HDTV or computer monitor I watch it on. This is hardly "4K quality" one would come to expect given the high praise the G7 has been given.

    Yet when looking back on all the video samples I checked out before buying I noticed no one ever pans their G7, it's always a static shot. Here's a sample, below. I was just quickly documenting the utter destruction that's coming near my home for the sake of a new highway, so don't expect Fellini ;-)

    You can see it as I pan across the road, and when the sky comes into view. And, yes, even though the camera is a month old I cleaned the sensor and the lens.

    NOTE* The effects I'm talking about can be seen within the first 40 seconds of each video. No need to watch the whole thing.



    You can also see it as I pan up in this video I shot yesterday while testing a variable ND filter that just came. Just to the right of center. This is a different kind of "dirt effect".
     
    Last edited: Aug 9, 2016
  2. Bif

    Bif Mu-43 Veteran

    380
    May 28, 2012
    San Angelo TX
    Bruce Foreman
    I don't see it. Try a diffrent monitor.
     
  3. panamike

    panamike Mu-43 Top Veteran

    979
    Jul 5, 2016
    Lincolnshire UK
    Its long time since i made films and that was with HI8,you say no one pans with the G7 in my day no one panned any way or zoomed much as it can be very unsettling for the viewer,have you checked other cameras to see if film makers pan much with them.
     
  4. Duke Sweden

    Duke Sweden Mu-43 Regular

    66
    Aug 9, 2016
    Duke Sweden
    Hey guys, thanks for responding. Bif, I have two monitors hooked up to my PC, one is a 32" HDTV and the other a 22" PC monitor, and the same exact pattern appears on both. I was watching the second video again and it appears to be caused by the weird foliage on that one tree (I don't know what type of tree that is). It doesn't have leaves, it has like a stringy moss which I'm guessing now any consumer camera may have a hard time handling.

    panamike, I'm not saying I pan and zoom as a regular part of my "repertoire", as it were. As you saw I was just doing some quick handheld shots. Anyway, since neither of you saw what I was talking about it would be hard for you to know what would cause it. Again, I'm going with the weird mossy foliage on the second one.

    Thanks again for responding.
     
  5. DanS

    DanS Mu-43 Veteran

    391
    Mar 8, 2016
    Central IL
    Duke, I think I see what you are talking about. To me it looks more like skin oils or some other type of semi-clear thin liquid got on the sensor. Have you run the sensor cleaning routine? You might have to send it in for cleaning if the issue persists.
     
  6. gcogger

    gcogger Mu-43 Veteran

    342
    May 25, 2010
    UK
    Graeme
    I'm not too familiar with video, but I wonder if they're compression artefacts? Are you recording on a high quality (bit rate) setting?
     
  7. Duke Sweden

    Duke Sweden Mu-43 Regular

    66
    Aug 9, 2016
    Duke Sweden
    I cleaned the sensor and they appear to be gone. I've had my suspicions about this camera being new when I bought it, since it was also missing the warranty card.

    gcogger, I'm recording at 4K 100 mbps. My Nikon D5500 never did it. I'll try recording at 30fps instead of 24fps and see if that makes a difference.

    Thanks, guys.
     
  8. gcogger

    gcogger Mu-43 Veteran

    342
    May 25, 2010
    UK
    Graeme
    LOL - well that's not it then :)
     
  9. Duke Sweden

    Duke Sweden Mu-43 Regular

    66
    Aug 9, 2016
    Duke Sweden
    I happened to find another G7 video sample today, and for one short burst the guy panned as he followed some birds flying by and I could see the effect in his video. I wonder if it's because a 1080p monitor can't handle 4K. Ya think?
     
  10. DanS

    DanS Mu-43 Veteran

    391
    Mar 8, 2016
    Central IL
    That's not the issue. If you shoot 4K 30p the bitrate will be ~100Mbps, if you upload that to YouTube, it will get re-encoded and down sampled to 45Mbps max. So that alone can cause pixelation/graininess, and loss of quality. That's is why people always say don't trust YouTube video quality.
    Recommended upload encoding settings - YouTube Help

    What I saw in your video didn't more around the frame as you panned. Pixelation/graininess, moves around the frame, because its related to the detail/moment. Either your sensor is dirty (the cleaning routine won't get everything) or faulty. You should have it looked at by a professional.
     
  11. Duke Sweden

    Duke Sweden Mu-43 Regular

    66
    Aug 9, 2016
    Duke Sweden
    I shot that before I cleaned the sensor. It's gone now. What I saw in the youtube video I referenced is similar to what I'm talking about now. It's like shooting through a dirty window screen. You don't notice it when the camera isn't moving but you do if you pan.

    Thanks for the link but I use Adobe Media Encoder's youtube 4K preset (1080p preset before I got the G7).

    One other question, since it's kind of related. I've seen some nice color grading on G7 footage, but with me it seems to "break" too easily. Do you have any suggestions there?
     
  12. DanS

    DanS Mu-43 Veteran

    391
    Mar 8, 2016
    Central IL
    What do you mean break?
     
  13. Duke Sweden

    Duke Sweden Mu-43 Regular

    66
    Aug 9, 2016
    Duke Sweden
    I thought that was a common slang. You know, you tweak a setting and the quality gets really crappy. You can undo it, but in other words, it's very difficult to tweak color correction and grading, as opposed to working with ProRes HQ, for example.
     
  14. DanS

    DanS Mu-43 Veteran

    391
    Mar 8, 2016
    Central IL
    ah, ok.

    Try Davinci Resolve.


    if your using windows try something like this.
    1. Convert the UHD h.264 out of the camera to UHD DNxHR HQ or SQ using ffmeg or something similar.
    2. Color grade the UHD DNxHR in Davinci Resolve
    3. Ouput a graded UHD DNxHR master from resolve.
    4. Convert/down sample the UHD DNxHR to whatever final deliverable format you want using ffmpeg.

    The number one thing you are going to need to do is stop using Adobe Media Encoder presets, as they are all about getting a given file size not maintaining a given video quality. Something like ffmeg will let you tune the settings to get the quality you want, and is usefully faster then all the major video editors.

    Another thing to remember, is you can only push the footage out of the G7 so far, because it's 4:2:0 8 bit color. 4:2:2 8/10 bit or even 4:4:4 12 bit can be pushed a lot further just like a raw image can me pushed more than a jpeg, as the file contains more data.

    You might want to consider this guide, I purchased it, and it's pretty good, and it does cover grading.
    Panasonic G7 Video Guide – Shoot Video on the Panasonic G7
     
  15. Duke Sweden

    Duke Sweden Mu-43 Regular

    66
    Aug 9, 2016
    Duke Sweden
    I can't use Resolve. I don't have an Nvidia card, just one of those crappy Intel 3D graphics proprietary cards.

    Believe me I've been transcoding to DNxHD since my D5500 days. Doesn't help. It has to be my work flow because I know it can be done.

    I'll give ffmpeg a try.
     
  16. DanS

    DanS Mu-43 Veteran

    391
    Mar 8, 2016
    Central IL
    You are going to need an actual video card to do just about any color grading. As pretty much all the grading software leverages the gpu.

    what bitrate where you using?

    For the G7 footage I've gone h.264 UHD -> dnxhd 145 HD

    tonight I've been playing with h.264 UHD -> dnxhr sq HD
     
  17. Duke Sweden

    Duke Sweden Mu-43 Regular

    66
    Aug 9, 2016
    Duke Sweden
    But now I don't know if you're talking about speed and ease of use when working with video files, or actually color correcting/grading. Sorry if I've been the cause of the confusion.

    btw I downloaded ffmpeg and I remembered I had downloaded it before. How do you use it? There are no executables, only files.
     
  18. DanS

    DanS Mu-43 Veteran

    391
    Mar 8, 2016
    Central IL
    It's both, you need a good video card when you are edditing/grading so you can validate the changes you are making. If the card isn't up to snuff, the video won't play back at a rate good enough for you to work with.

    When rendering out your final cut, it only effects how long the render will take. Trust me though, you don't want to be doing your final render at 1 or 2 fps.


    You want the "static" builds, those are compiled down to a single executable file.

    windows: Zeranoe FFmpeg - Builds
    OSX: static FFmpeg binaries for Mac OS X Intel 64bit

    ffmpeg has more of a learning curve, because its a command line application, but its faster than pretty much everything else.