Panasonic GH-4 V-Log upgrade.

I’ve been asked by quite a few people now to comment on the upcoming GH-4 V-log option. For a start I haven’t tried it for myself, I have only seen content that’s been posted online, so it’s hard to tell a great deal about it especially as the online examples I’ve seen so far have been terribly exposed, typically grossly overexposed (but maybe that’s a design characteristic). What I know for sure is that it brings an improvement in dynamic range from 10 stops to 12 stops and that’s obviously a very big improvement. But, it has to be considered that many video cameras have been providing 11 stop ranges for many years, so in many respects this is just the GH4 catching up.

I’m afraid I had to laugh at some online V-log examples where the shooter had applied look up tables for Arri’s LogC to the footage. This clearly demonstrates a complete lack of understanding of log curves and LUT’s and how they work. You’re never going to get a great image by applying a LUT designed a 14+ stop input range and wide colorspace to footage with narrow colorspace, totally different luma recording range and only 12 stops. I really wish people would learn how these things actually work before blindly assuming that “because it’s log it must be better” and “because it’s an Arri LUT it’s going to make my camera look like an Alexa”. Sorry, but it really isn’t that simple and this is a case of the blind leading the blind. If you want to use LUT’s then V-Log will need it’s own dedicated LUT’s as it’s unlike any other log curve out there. The majority of log cameras have ranges of at least 13 stops (2 x the range of the GH-4’s 12 stops) and more commonly 14 stops or more.

Clearly, it’s an improvement to the camera, but this upgrade really reminds me of many of the flat profiles for the Canon 5D that don’t do much other than making the picture look, well, flat. They don’t actually add any dynamic range. I’d be really interested in the noise in the shadows from the GH4 in V-Log. My suspicion is that it will be quite noisy or heavily noise reduced compared to the standard profiles.

14 thoughts on “Panasonic GH-4 V-Log upgrade.”

  1. Hey Alister,

    Sorry you didn’t care for my footage. I’m still coming to grips with V-Log L, as many others will be shortly. I’ve never claimed to be a colorist, but was fortunate to have an opportunity to test V-Log early. Of course I’d jump on the chance!

    As far as the Alexa LUTs, I was just dabbling to see which Log format the V-Log was similar to. Trying various SpeedLook LUTs on the files seemed a quick way to see how the files responded. To my surprise, and as noted in the video you failed to link to, I was surprised to find that the image didn’t require much tweaking after applying the Alexa LUT.

    Since it will probably be some time before I see V-Log L LUTs in my favourite LUT packages, this looked like a great time saver as we wait for the (obviously superior) real V-Log L LUTs to be released. I was looking to share in my journey as I discovered new things.

    I have a great deal of respect for the work you do and have followed you for some time. I hope that you continue to produce your great reviews and tutorials, despite my reservations about this article.

    Jordan Drake

    1. Well I’m sorry Jordan, but it wasn’t your footage I was referring too. I’ve seen many examples of V-log with Arri LUT’s applied and they all look wrong, there is a big colorspace and recording range missmatch. How can a LUT deigned for a 14 stop luma input range of 3.5 to 95 IRE possibly work well with a 12 stop signal recorded across a 0 to 109 IRE range? The output will have clipped highlights, look flat and lack color. Sure you might get the occasional happy accident where the results look OK, but if you don’t have the right LUT the you would be better off with an S-Curve and conventional grade. Either that you buy yourself a Macbeth chart or DSC chart and make your own LUT using Resolve, it would only take a few minutes.

  2. Alister,

    Thank you for writing this. There are many people in who really mess up my profession by saying they are color artist or graders. Most people simply have a piece of bad information in their head that applying a lut is fixing color, when simply your suppose to color correct and grade your footage before you even add a lut, and your certainly not suppose to add the same lut to the entire working project because scene can change dramatically. I’ve been trying to get my hands on a 30 second clip, untouched right out of camera with the users settings to create a lut… I’ve been very unsuccessful in doing so as everyone is a conservative on the net. I do ask my self many questions when shooting with the GH4 what will change? Even if you gain a extra 2 stops of Dynamic range, does the compression change as well, There is a major difference when working with RAW footage compared to a compressed GH4’s 8-bit 4:2:0 file, I guess time will tell, but these people online need to shut off the you tube and learn from the pros about luts and logs. Just the other day a person posted online that they where selling DLog, it was simply a miss understanding of terms but people still eat it up, the user simply made a custom log setting, unknown, then made a custom lut that looked okay for that one shot, this was simply a custom lut they made not a Dlog. OH THE INTERNET HOW YOU’VE FAILED ME!

  3. I believe VLOG-L rolls off at 79 IRE according to Barry green and LPowell.
    Its designed for the Varicam but without the 2 extra stops (14+).
    So apparently although it uses the full range of the sensor, there are some problems fitting the range into an 8 bit codec.
    And this would explain why most of the examples you have seen are grossly overexposed, its quite possible that the histogram does not accurately display the exposure in the beta cams.
    Anyway there has been a lot of discussion about this in dvxuser and also Personal View.

    1. I see that. VLog is another modified Cineon curve. It’ couldn’t be a worse choice for 8 bit recording. What you really want is a log curve that uses the full 0 to 109 IRE range.

  4. @alisterchapman
    Thanks for all your informative posts!!

    Trying to understand when and how to properly use V-Log L with GH4..(new to log world)..

    It seems that 12 stop DR is recorded across the 12,5 to 79 IRE range (18% at 42 IRE and 90% reflectance white at 61IRE)….

    Pansonic has a V-Log to 709 LUT but it is supposed to be used for +0 exposure….I’d like to overexpose by 2/3-1stop (for cleaner image)….

    1)is there any chance any of your S-log3 +1 LUT’s will be somehow suitable for Vlog-l to 709 conversion?
    2)If i import the V-Log L footage (in PPro CC2015) and lower exposure by 1stop and then apply the panasonic’s Vlog-L to rec709..will this be ok?

    Kind regards,

      1. Thanks!
        I’ll try your Slog 3 LUT’s.

        I’ve read in one of your articles that your lut’s must be treated as input lut’ that means that i must apply them as soon as my footage is imported into my NLE (before making any exposure or other adjustments)..

        What is your recommended IRE scale for skin tones in slog 3 ?(should be the same for vlog-l..)..i’ve read many of your articles these 2 days but couldn’t find any info(except for when using specific lut’s like 709(800) should be at 65-70)…

        1. LUT’s are best used as output LUT’s when grading. So apply the LUT as an output LUT, then grade the material. This way you should be grading the full range of the original material before the LUT calculations are performed. A lot depends on the grading software. If you are using something like resolve it makes little difference where you place the LUT as internally Resolve uses 32 bit math and always retains the full range of the clip. But a lot of edit software is only 16 bit and can end up restricting the range and accuracy.

  5. So just to be sure i understood it.
    Import log footage into NLE,make adjustments(highlights-shadows etc),grade and apply a lut (like your’s slog3 to 709) then export…

    About skin tones?

  6. You apply the LUT first, but as an output LUT or if using something like Premiere as the bottom/last effect in your effects tree. Then you do the grading with a color correction effect that is placed above or before the LUT. This way internally the software processes your grade first, then adds the LUT, but what you see is always the combination of the two.

  7. Crystal clear!

    Does any of your LUT’s transform Slog3/Sgamut 3 to rec 709 gamma and 709 colorspace?
    I’ve checked them and all of them seem to be Slog3/Sgamut 3.cine to 709..

    1. I’ve done my LUT’s for S-Gamut3.cine because the only camera that can actually deliver the full S-Gamut3 range is the F55. If you use a S-Gamut3.cine LUT on S-Gamut3, unless it’s actually from an F55 a simple saturation tweak will be all you need.

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