Small surprise: GH4 seems to focus slower in 4K recording mode (while it’s damn fast at 1080).

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Our friend Frederick compared the GH4 and GH4 AF performance and discovered an interesting drawback of the GH4 in 4K mode:

I have tested the autofocus performance of the GH4 with the GH3 during video recording. This demanding test shows that the GH4 indeed does improve upon the GH3 in 1080p mode. In 4K mode, though, the autofocus is rather poor.
http://m43photo.blogspot.com/2014/05/recent-micro-four-thirds-cameras-have.html
I tested using both the 12-35mm and 35-100mm f/2.8 lenses.

It’s the first time I hear about that “drawback”. Hope other readers will test this too and confirm (or not confirm) the slower af in 4k mode!

GH4 North American preorders, shipping date and price:
GH4 camera at Amazon, Adorama, BHphoto, Ritz Camera and Panasonic. Price: $1,698. In Canada at Vistek.
GH4 camera with interface unit at Adorama and BHphoto. Price: $3,298
Interface unit only at Amazon, Adorama, BHphoto and Panasonic. Price: $1,998

GH4 Europen preorders, shipping date and price:
Germany: Wexcameras, Marcotec-shop.de.
UK at Wexphotographic, CameraWorld, UKdigital, CVP, TipTop.
Holland at Fotohanskeuzekamp.
Belgium at Fotokonijnenberg.
Norway at Fotovideo.
Sweden at Cyberphoto, Skandinavianphoto.
Finland at Telefoto, Topshot, Verkkoauppa.
France at Photocineshop.
Spain: Fotoboom.

Asian preorders, shipping date and price:
Digitalrev and Digidirect Australia.

4K cards
Kingston 16-32-64 GB SDHC UHS-I Speed Class 3 at Amazon (Click here), Adorama (Click here) and BHphoto (Click here).
Sandisk 16-32-64 GB Extreme PRO SDXC UHS-II Memory Card at Amazon (Click here), Adorama (Click here) and BHphoto (Click here).
Transcend 64-128 GB High Speed 10 UHS-3 at Amazon (Click here) and BHphoto (Click here).
Panasonic 16-32-64 GB SDHC-UHS-I U3 Card (90MB/s) at Adorama (Click here) and BHphoto (Click here).

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  • explorer76

    I doubt that anyone doing serious enough video work to need 4K would use video AF.

    • Eno

      Actually you are wrong, a lot of serios videographer, including me, make a good use of a good AF in video mode. But the better screen and focus peeking are a nice additions to Gh4 compared to my old Gh3 so I forgive Panasonic for the rather disappointing AF in 4K.

      • Pietz

        having an af like the a6000 would have been so great.

        • Clifford Rockwell

          How is the a6000’s AF performance while shooting 4K?

    • Mr.Chainsaw

      According to all the FF trolls you don’t need to focus anyway with MFT because you can’t get shallow DOF :)

      • FullFrameForever

        This is correct! The sensor is simply too tiny.

        • PBR

          Just a heads up, beginners might not realize that for video, a smaller sensor is better. Large sensors need more down sampling which creates more artifacts.

          Cheers!

          • Tom

            Large sensors need more downsampling? Sensors with more lines need more downsampling, and this is only true of those amateur cameras that discard lines. I believe GH4 discards the lines in eccess. As usual: 1) check 2) ask .

            • Methodman

              You should check. 5D3 has more artifacts from down sampling than a GH4. I thought this was common knowledge at this point.

            • peevee

              GH4 does not discard lines within 16:9 crop (obviously, it discards the one outside).

  • ThisIsGenious

    Testing rig is of the utmost awesomeness!

  • jon

    Probably needs more CPU to encode 4K video, leaves less for the AF? (I’m just guessing, I have no idea how camera OSes work).

  • Dun

    4K has a lower frame rate, which decreases the focusing speed as he says.

    • Rambalac

      In 1080p 24 оr 30 it’s focusing same fast as in 60, and still much faster than in 4K
      In 4K even display becomes 30fps

  • Jens

    Difference in frame rates is most likely (at least part of) the culprit. Shooting at 50p – as he did with both the 1080 examples according to his blog – he’s got twice the number of frames with which to scan for contrast and detect focus compared to C4K 25p. A more apt test would be to shoot everything at 25p. I would wager the 4K is still slightly slower due to processor demands, but it should at least prove that frame rate has a significant impact on AF speed.

    • Rambalac

      No, 1080 25 or 30p is still fast, much faster than 4K

  • george

    When use slower lens, it is more the case. I used 100-300mm f4-5.6 to track an airplane. it is harder to get auto focused when in 4K mode.

  • Tom

    Damn! Oil on the nerdic fires.

  • Saito

    I have another issue with my Gh4, i have a lot of jitter/strobing/lagging whenever i pan, tried every frame rate and every settings.

    • tom

      Check your shutter speed. Rule of thumb is to use roughly 2x frame rate, so 30fps should be 1/60 or as close you can get.

  • T Ra

    Actually you posted a video review a few weeks ago that addressed the poor AF. I’m trying to remember which one it is but they were testing the camera out around their not-that-dark camera store trying to focus on a walking subject and the results were pretty depressing. Shame because i wanted to use this camera with a glidecam.

    • tom

      Get a very wide lens and run manual focus. This will give the best and most professional results on a glidecam.

  • Disappointed

    HOW COULD YOU DO THIS PANASONIC? STOP THE MADNESS AND MAKE ME A PERFECT FULL FRAME CAMERA!!!
    Aarrgh!

    • Yarr

      If they chose to, they could. Perfect.

      • Tacothatcrapsicecream

        Perfect

  • mekalush

    when it’s sale in europe?

    • mekalush

      may 2015??

  • Someonewillmissthesarcasm

    Does anybody know if it focuses faster than other hybrid cameras in head to head 4k shooting?

  • mimstyle

    sorry in this video gh3 is faster when the move stop

  • D3xmeister

    Yes I posted about this on dpreview a few days ago. I noticed this on the first day with the GH4

  • peevee

    I would not say that even in 1080p it is any faster than GH3. Strange. What lens was that?

  • fuzzynormal

    Ugh. Shooting video with autofocus? Bad idea anyway. Manual focus lenses are much more appropriate for most filming.

    • glnf

      Ugh. Shooting 4K without autofocus? So you have a professional focus puller or shoot trees growing. Othervise – good luck!

      • fuzzynormal

        Photographers and cinematographers have managed somehow for more than a half century. And they’ve been doing it with a format higher res than 4k.

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