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Cary Knoop

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Posts posted by Cary Knoop

  1. 11 minutes ago, marcuswolschon said:

    ?????

    10 bit require 2 bit more storage space then 8 bit and it can encode a value range that is 4 times the size.

    Wait hold on folks, I apologize I am totally wrong on the bit size increase!

    I just cleared up my brain fog! :flushed:

    Of course, while the information quadrupled the required space is only 10/8 more, a factor of 1.25!

    shame.jpg?itok=izFDryyo

     

  2. 12 minutes ago, zetty said:

    From the point of view of how the data is stored, 10 bits is only 2 bits extra over 8 bits -- thus, while providing immensely more values to work with, it doesn't take as much space when stored. So it doesn't matter if there are more possible values for each pixel, what matters is how much space does it take to store the actual value of the pixel.

    I think you are wrong. 

    It surprises me, with a coding background you should readily understand that 10bit data requires 4 times as much storage as 8bit data. .

    10 bit requires 1024 distinct values as opposed to 8 bit requiring 256 distinct values.  How does that not take four times more space?

     

    Edited to add: I am wrong, 10 bit is only 1.25 times the size of 8 bit!

     

  3. 34 minutes ago, zetty said:

    10 bit certainly isn't that much more from the point of view of how information is stored digitally

    I beg to differ. 

    If we take a standard 8 bit 4:2:0 video and discard for the sake of simplicity video levels, transparencies and gamut constraints we have:

    3 x 2^8 bits of information per pixel subsampled to 4:2:0 which is: 384 values per pixel

    For 10 bit video this becomes:

    3 x 2^10 bits of information per pixel subsampled to 4:2:2 which is: 2048 values per pixel

    That's an effective factor of 5!

    34 minutes ago, zetty said:

    And 4:2:2 would only double the vertical colour resolution, so it should only be a fractional increase?

    I would not call that fractional, it is twice as much as 4:2:0 in an absolute sense and it is 25% more with respect to the 4:4:4 baseline.

    You seem to grossly underestimate the sparsity of 4:2:0

    8d37969f3d02416198576f49430eaf02

    Your document talks about saving bandwidth when the destination is going to be 8 bit.

    Now do encoders need 5 times as much bandwidth for 10 bit 4:2:2? 

    Of course not, the more data the more effective the compression (one would hope) but I think it should be somewhere between 250 to 300 Mbps for H.264 and about half of that if it is H.265.

     

  4. 6 hours ago, jonpais said:

    10 bit 4:2:2 less so because I never do any heavy grading, just some color correction and a little LUT, usually no more than 15%.

    If, and that is a big if, the GH5 is true 10 bit, it should have a significantly higher image quality. I say true 8 bit because if it is the same sensor as the latest GX and G cameras I believe the S/N ratio will be too low to have true 10 bit.  You might as well take an 8 bit camera and dither it to 10 bit with Gaussian noise.

    Nevertheless I will soon be on the pre-order bandwagon!

    By the way I think the end of 8 bit video is on the horizon.  In a year from now I predict that all new pro and prosumer cameras will be 10 bit cameras supporting HDR.

     

     

  5. 16 minutes ago, Don Kotlos said:

    Here I made it easier for you to see:

    Screen Shot 2016-12-26 at 1.46.19 AM.png

    Screen Shot 2016-12-26 at 1.46.33 AM.png

     

     

     

    Going that extreme I would no longer define as color correcting, I think that is doing something very wrong with a video.

    But alright now please do the same extreme curves in Resolve.

    I stand by the video!

     

  6. 27 minutes ago, Don Kotlos said:

    It is true. Maybe its hard for you to see in this small size but the vector scope also shows a difference. 

    Here is a video comparing the two NLE's.  As you can see curves do not change hue both for Premiere Pro and Resolve.

     

     

  7. 4 minutes ago, Don Kotlos said:

    Adjusting contrast with either the slider or the curves in Lumetri panel changes the hues of skin tones! Not the way it is expected at all.

    I am sorry but that is simply not true, just watch the vector scope!  Saturation (obviously) changes but hue does not!

    By the way, and you probably know this already, if you want to guard against saturation changes (although it can obviously not be totally prevented) you could do your modifications in an adjustment layer with a Luminosity blend mode.

     

  8. 32 minutes ago, Don Kotlos said:

    While exposure, contrast, curves in Lumetri color panel suffer from this, the classic old style Brightness & Contrast Effect in Premiere behaves the same as FCPX and adjusts levels by shifting all channels with an additive term. This results to better skin tones, so if you want to adjust contrast or reduce exposure in Premiere you should use this effect and avoid using the exposure/contrast/curves in Lumetri color panel.

    I partly agree and partly disagree.

    I agree that the Exposure slider in the Lumetri panel is not good (although I think things have improved somewhat in CC2017) and I would agree to generally avoid this slider altogether. I disagree with you about the Contrast slider. This slider is the classic s-curve and in my opinion works just fine! 

    The Contrast slider in the Lumetri panel is very dissimilar to the Contrast from the Brightness & Contrast effect (or the ProcAmp effect), it fact it affects the dynamic range of an image not the contrast. 

    I think the Curves in the Lumetri panel are just fine and operate as expected, I really do not understand on what grounds you base your criticism of Curves.  In fact you can completely copy the Brightness & Contrast operations with curves!

    In addition I think the Color Wheels in the Lumetri panel are very good as well.

     

  9. Just now, jase said:

    Forgive me my stupidity, but are you saying that I shouldnt use a 60p recording in a 24p timeline without applying slowmotion? E.g. only if I would apply the slowmotion it will look good according to your opinion? If yes, does the same apply to 50p files in a 25p timeline which is not slowed down?

    Without slowmotion going from 60p to 24p is not going to look good, but sometimes you have no alternative. 

    Going from 50p to 25p is not perfect either but a lot better than going from 60p to 24p because you do not need blending and the cadences are not disturbed.  You could skip every other frame and whether it remains smooth depends partly on the shutter angle. 

     

  10. Just now, jase said:

    Cary, could you elaborate a bit? I always thought that recording in 60p and using that in a 24p timeline to have 2,5x slowmo is good practice?

    Yes, for slow motion it is a great option! 

    I was actually talking about converting 60p recordings to 24p while keeping the same speed. 

    You wind up having to blend frames or remove them.

     

  11. 16 minutes ago, jase said:

     I am using the Sigma 18-35 on my GX80.

    That is a great lens.

    Take a Speedbooster with the Sigma 18-35 and the Sigma 50-100mm and you have a wonderful combination!

    It would be even better if they made a 30-60mm to complete the set.

    On the wide side what do people think about the Tokina 11-16mm f/2.8 Pro? 

    With the Speedbooster you get an 8-11mm f/2.0 lens!

     

  12. 40 minutes ago, DBounce said:

    Both images seemed exposed similarly.

    The levels comparing the two cameras are clearly off in the video.

    Here is an image with two more or less similar frames (Olympus is left, Sony is right) after the levels are corrected:

    corrected levels.jpg

    Neither frame has crushed blacks!

    If look at the negatives and expand the blacks a little, there isn't much of a difference:

     

    negative.jpg

  13. On 12/19/2016 at 7:54 PM, Zak Forsman said:

    My production company produced this microbudget feature, shot on the GH4. Only have the :30 teaser available right now. But the feature will be released next year.

     

    Nice, but I jumped from my chair due to the extreme loudness of this teaser.  :)

    I ran a loudness check on your footage, it's around -9 (ATSC A/85 LKFS).

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