GH4 HDMI out for FPV

Discussion in 'Cameras' started by Steve Maller, May 5, 2014.

  1. Steve Maller

    Steve Maller UAV Grief Counselor

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    That's great! Is that actually in the manual or did you discover that some other way?
     
  2. TJ_Sheridan

    TJ_Sheridan New Member

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    Like I said, I bought a sync controller for the GH4 so I could sync two cameras for 3D stereographic time lapses. The controller uses the video signal from the AV port to detect disparity between the two cameras. The manual for the sync controller mentioned that you had to hold the trash can button down for 5 seconds in order to activate the AV video signal for live feed.

    I didn't see it in the GH4 manual, so I don't think it's common knowledge. I was super excited when I tried it and realized it worked. I did a record test in at 30fps, and it seemed to function fine. But when I went back and tried it again, the live video feed turned off when I hit record. So I'm not sure what happened that it worked the first few times I tried it, and then it didn't. I was changing stuff in the menus, so I might of messed something up. I'll do some sleuthing and see if I can figure out what I did the first time to get it to record while in live view.
     
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  3. Steve Maller

    Steve Maller UAV Grief Counselor

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    I ordered the AV cable today. Will try it once I receive it! Thank you again.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Give that man TJ a medal! I've been pondering the same problem -- I confess I had not quite got to the stage of "Oh, I know, let me try holding down the trashcan button for five seconds while I power the camera on..." I'm sure I would have got there in a few decades, though. :rolleyes:

    Andy.
     
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  5. TJ_Sheridan

    TJ_Sheridan New Member

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    :D I like medals! Weird thing to get a medal for, but I'll take it. Can I trade my medal in for an M5 gimbal that works?

    Andy, to be clear, you don't hold the trash can button down WHILE you power the camera on. You can do it at any point. The camera just needs to be powered on when you hold the trash button down for 5 seconds. And from what I can tell it's a toggle. When I powered the camera off and back on again, my AV video out was still working. I don't think you have to do it every time you want video out.
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Of course you can.
    However, I should warn you that I'm only a volunteer moderator so I have absolutely no authority to make a statement like that! :)

    Andy.
     
  7. TJ_Sheridan

    TJ_Sheridan New Member

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    For those of you who care, I got the G7 today. It's 150 grams lighter than the GH4.

    It DOES have the 5 second trashcan button toggle for turning on live AV out. Yes!

    The 14-42 lens is a new design, and it's incredibly light and small. It's surprisingly sharp for a kit lens, very usable for aerial work. No weather sealing on the lens or camera, but how many people fly in the rain?

    Overall, I'd say it's the biggest bang for the buck on the market right now. Pristine 4K, with a quality wide angle zoom, and a free shotgun Microphone (if you get the Adorama deal before it expires). It's a GH4 for $400 basically.
     
  8. Howard Dapp

    Howard Dapp Active Member

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    Regarding those Amazon hdmi to AV converter boxes, I ordered two some time ago and only one worked with the GH4/Epic but both worked with the 5D. They look identical on the outside but when opening you can see the difference. The box with the heatsink is able to convert 720 and 1080 but the other is limited to 720. image.jpg
     
  9. Steve Maller

    Steve Maller UAV Grief Counselor

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    TJ, can you confirm it works in 4K also? And does it work in either System Frequency (24.0 or 59.94), too?
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Thanks for the clarification.
    Mrs. Google is showing that the press-and-hold the trash can has been around since the Panny G1, G2 etc. -- not that steals any thunder from you for discovering it.
     
  11. TJ_Sheridan

    TJ_Sheridan New Member

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    Steve,

    I pulled out my G7 and did a full record test. Turns out, it shuts off the live video feed when you record. When I did my first test with the GH4 it allowed me to record during live video, but I'm not sure what mode it was in, or which GH4 I was using. One of them is on the original firmware, and the new one I just got is on a V2 firmware. It may be different between cameras, and I didn't try all frequencies, so it may not work in all conditions or in all video modes. I just know it worked in whatever mode I was in at the time. I've changed modes several times today at several different video shoots, so I'll have to go back and figure it out. I assumed when I got a live video feed out on the G7 that it would record as well, but it didn't. Grr.

    So I apologize for getting all your hopes up prematurely!

    Looks like the G7 will need a video conversion box after all. So frustrating. No big deal, I just got two from Amazon a few days ago. Hopefully the brands I bought will work. I'll try and do a full battery of mode tests and let you know which frequency & modes it works in, and report which modes don't work.

    Guess I have to give me stupid medal back. Dangit.

    Andy, when you searched Google, did it mention anything about recording during live view?
     
  12. Howard Dapp

    Howard Dapp Active Member

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  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    TJ:
    1. No, you don't have to give the virtual medal back. You deserve it for making the discovery in the first place!
    2. You also deserve it for posting that you might be wrong. If only more people would admit to being wrong! :)
    3. I don't remember seeing whether or not recording in LiveView was feasible -- but I can see why it might not be because to maintain the video output and record might increase the compute power required on the image processing system.

    Please keep us posted on your experiments....

    Andy.
     
  14. Steve Maller

    Steve Maller UAV Grief Counselor

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    The AV cable I ordered is expected tomorrow. I'll try and do a quick experiment to verify this functionality this weekend.
     
  15. Howard Dapp

    Howard Dapp Active Member

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    Just got the cable in today. I'll test those modes while recording.
     

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  16. Howard Dapp

    Howard Dapp Active Member

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    Well not so great news for GH4 FW version 2.2...

    - 4k/30p @ 59.94hz sys freq = AV signal = yes | AV signal while rec - No
    - 4k/24p @ 59.94hz sys freq = AV signal = yes | AV signal while rec - No
    - All 1080 modes @ 59.94hz sys freq = AV signal = yes | AV signal while rec - No
    - 4k/30p @ 24.00hz sys freq = AV signal = no | AV signal while rec - No
    - 4k/30p @ 50.00hz (PAL) sys freq = AV signal = yes | AV signal while rec - No

    No AV signal while recording for any rec modes. No AV signal whether recording or not while in 24.00hz sys req
     
  17. Steve Maller

    Steve Maller UAV Grief Counselor

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    Howard, thank you for doing the homework. I guess I could have saved $9.00 by waiting. :(
    TJ, did you see any AV signal whilst recording on the GH4?
    What Andy said (hard to expect that much CPU overhead would be available) makes sense. Twas too good to be true.
     
  18. Chris Delaney

    Chris Delaney Member

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    I've been following this. So I still need to get the box eh? Lol
     
  19. Chris Delaney

    Chris Delaney Member

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    Are the majority of you guys using the Hyperthin brand of hdmi cable? If not what brand? Thanks
     
  20. Steve Maller

    Steve Maller UAV Grief Counselor

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    I got the Panasonic cable, and I've confirmed Howard's findings that the AV adapter does not allow output whilst recording.
    Live view works, but once video recording begins, the AV output is stopped.
    #falsealarm

    HOWEVER, I just realized something, and this is significant:
    As some of you know, the GH4 has an unfortunate personality trait that limits its use for aerial stills. In addition to being resolution-deprived when compared to high-megapixel bodies like the 5D Mark III, it has a further limitation: if the HDMI cable is attached for FPV, the screen aspect ratio is switched from 4:3 to 16:9, even further limiting the still resolution because of the loss of horizontal scanlines.

    I just tested the GH4 with firmware 2.2 and the DMW-AVC1 cable, and it retains the GH4's full resolution when shooting stills and mirroring to my SmallHD display. To improve the experience, the review time should be set to OFF. I tried it with manual triggering of the shutter, and with the built-in intervalometer.

    So I recommend that TJ be allowed to keep his medal, but that he gets an asterisk in the Forum Hall Of Fame.:rolleyes:
     

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