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Andrew Reid

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Posts posted by Andrew Reid

  1. Compare it to the full frame Canon EOS 1D C that has a 1.3x crop in 4K.

     

    Let's get a few things straightened out regarding Joe and dafranking's thoughts here, because they don't make sense at all to me.

     

    1D C is different price bracket and an MJPEG codec. It isn't comparable to the GH4 on features and won't be comparable to the A7S on price most likely.

     

    It is old technology now.

     

    The GH4 is the most obvious candidate to compare upcoming 4K cameras to, it is the current benchmark. No other camera comes in at the same price point with this many features. The Blackmagic 4K has 8x larger file sizes which are impossible to archive over a years worth of shooting unless you are Donald Trump, yet it lacks even the most basic of features like histogram. Nice image under ISO 400 and I like the concept but sorry, it is not feature complete enough or ergonomic enough to compete with Sony or Panasonic, ditto the 1D C.

  2. Grading is a subjective art and I think some people on here have quite a narrow definition of what is 'right' or 'wrong'. If you don't like it fine, but don't try and put it down to an error or camera problem! I've intentionally chosen the look I wanted here, to bring out the warm magic hour sun and pink fleshy skin tones. If you have a different style feel free to download the ungraded clips from Copy and have a go yourself, then I will point at it and say you're "wrong", how's that?

  3. Hey Andrew,

     

    Basically if you take a grayscale gradient and you capture, resample, whatever.. from 10bit to 8bit, you wind up with 256 shades of gray (wow, just thought of a great title for a book).. and if you push the crap out of that, you will see banding, no matter what size the resolution is. In my experience, bit depth is more important than most of the other factors.

     

    But with a camera, there is Bayer pattern grain, algorithms and lots of interesting IP going on that can make it look much better.. but you're still stuck with the math.. 256 colors per channel at 8bit.

     

    Indeed, which is why when you downscale 4K to 2K and pack it into a file which can handle greater precision you have smoother gradients with finer steps in-between which respond better when you push them around in the grade.

  4. I don't think that video is relevant?

     

    On DSLRs with 1080p, the sensor gives a weak signal to the image processor. It is a signal that is heavily chopped and sliced before it even gets to the encoder and is turned into 8bit.

     

    On the GH4 the sensor gives a very strong signal to the image processor. It is a 1:1 pixel readout, debayered to 10bit 4:2:2... That is a lot of data for the encoder to work with. It is also a LOT more data than 1080p, around 4x more.

     

    So working with 4x more data in your grade is going to be a bit different to working with the usual 8bit 1080p from DSLRs.

     

    That it is still 8bit is kind of irrelevant - it is still 4x the data of 1080p and the stronger sensor signal. The whole internal imaging pipeline in the GH4 is 10bit 4:2:2.

     

    When you pack 4x the data into a 1080p file using your computer, you are throwing a lot of processing power at it.

     

    I can already see for myself how well the 4K data grades and how nice the 2K is from it when oversampled from 4x the data that you have usually!

     

    I must admit I do not understand the maths that well, I am not a mathematician but a filmmaker, so others may or may not be right on the maths... in the end I don't care... I have a pair of eyes and that is what counts :)



  5. Something I have discovered while editing all this GH4 4K material is that the 8bit codec Panasonic uses is quite complex and requires more power than ProRes. I have also found that the sequence settings and video proxy settings in Premiere are a good thing to pay attention to this time... the default ones no longer cut it.

    Along the way I have found a few tricks to get the colours in GH4 footage to absolutely sing with Film Convert and Premiere using the Alexa Rec 709 profile.

    Read the full article here
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