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    #11
    Senior Member macgregor's Avatar
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    Quote Originally Posted by starcentral View Post
    It makes sense to have more apparent noise at higher ISO's in general, so if you want a cleaner slog you can rate the camera at 1000ISO over exposing everything by one stop and then lowering it one stop in post for an approximate 6db improvement. It eats into you highlights but 1-2 stops is not necessarily going to be a big deal. Especially if in fact the A7s is capable of 14 stops as some other tests have shown.
    Yes, but just to clarify this is not what I was doing here.


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    Senior Member Samuel H's Avatar
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    So far I'm shooting both slog2 and cine4, but I think I like slog2 better. It sucks that it requires a bit more ND (not that much more: I'm overexposing slog2 by up to 2 stops, so if you are going to underexpose cine4 ISO 200 by 2 stops you basically need the same ND). And it sucks that it throws away such a big chunk of the codec's color space (it records 24-235 or something like that, which means 9.5M colors, instead of the 16.7M that cine4 can use). But the curve is just beautiful:

    slog2 (standard PP7, but with cinema color) (ISO 3200)
    a7s_slog2.jpg

    cine4 (standard PP6, but with cine4 gamma) (ISO 200)
    a7s_cine4.jpg

    flaat_11 on NEX-5N (Portrait with minimum contrast, sharpness -1, and DRO -1) (ISO 100)
    5n_flaat11.jpg
    Last edited by Samuel H; 09-01-2014 at 01:19 AM.


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    #13
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    Samuel, any chance you could try Macīs tweaks to the cine4 profile, and plot a curve for that?
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    #14
    Senior Member Samuel H's Avatar
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    Yes, of course. And I also have to test K-log. I was saving those for whenever I do the thorough a7s vs BlackMagic test, though... Probably next week.


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    #15
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    The very last comments on Alister Chapmanīs A7s Exposure article is a direct comment on this thread. Interesting what he says about the cine profiles being max 11.5 stops by design, and the slog2 being a 14 stop curve. He also seems to mean that the DR differences are greater between the slog2 and cine profiles than what the latest tests here have indicated.

    http://www.xdcam-user.com/2014/08/ex...-and-exposure/
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    #16
    Senior Member Samuel H's Avatar
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    I think the issue is that Alistair Chapman is talking about the theory, we are testing it in practice. So, that should read: "the DR differences SHOULD BE greater between the slog2 and cine profiles than what the latest tests here have indicated". And I aggree: slog2 should have the 14 stops of DR that Sony promised, and the difference with cine4 should be readily apparent. But it isn't. Dear Sony, I'm eagerly awaiting the firmware update that brings those 2.5 extra stops of DR to the a7s+slog2.
    (edit: I doubt that firmware update will ever come, but here's a more realistic request: right now, recording externally, you get one stop extra in the shadows, but lose one stop in the highlights because something goes wrong and it clips sooner; fix that highlight thing with a firmware update and the a7s will be clearly above any other camera in its price bracket in terms of DR)

    Of course, there's also the possibility that we may both me screwing up in post. But I doubt that's the case: I trust macgregor to be doing his post work right, and I seriuosly doubt that, if he made a mistake, I would make exactly the same one.
    Last edited by Samuel H; 09-02-2014 at 06:24 AM.


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    #17
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    Quote Originally Posted by Samuel H View Post
    I think the issue is that Alistair Chapman is talking about the theory, we are testing it in practice. So, that should read: "the DR differences SHOULD BE greater between the slog2 and cine profiles than what the latest tests here have indicated". And I aggree: slog2 should have the 14 stops of DR that Sony promised, and the difference with cine4 should be readily apparent. But it isn't. Dear Sony, I'm eagerly awaiting the firmware update that brings those 2.5 extra stops of DR to the a7s+slog2.
    (edit: I doubt that firmware update will ever come, but here's a more realistic request: right now, recording externally, you get one stop extra in the shadows, but lose one stop in the highlights because something goes wrong and it clips sooner; fix that highlight thing with a firmware update and the a7s will be clearly above any other camera in its price bracket in terms of DR)

    Of course, there's also the possibility that we may both me screwing up in post. But I doubt that's the case: I trust macgregor to be doing his post work right, and I seriuosly doubt that, if he made a mistake, I would make exactly the same one.

    Thanks for all the detailed info. Following this thread closely.
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    #18
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    Quote Originally Posted by benjaminreece View Post
    Thanks for all the detailed info. Following this thread closely.
    +1


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    #19
    Senior Member starcentral's Avatar
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    Quote Originally Posted by Samuel H View Post
    slog2 should have the 14 stops of DR that Sony promised, and the difference with cine4 should be readily apparent. But it isn't. Dear Sony, I'm eagerly awaiting the firmware update that brings those 2.5 extra stops of DR to the a7s+slog2.
    I am of the belief that the "benefits" of slog (higher dynamic range) over the cine's or even hypergammas are actually not all that readily apparent and here's why:

    The cinegammas on the Sony's are mostly 460% dynamic range curves whereas with slog1 it is 800%, and slog2/3 it is 1300%. What these numbers represent are the brightness levels above 90% white reflectance which can be recorded using the specific gamma curve. Impressively the HyperGammas (on the Sony F5/F55) now can achieve 800% dynamic range which is equivalent to the original slog without all the meticulous exposure and de-slogging in post that goes along with it. (I've used HG7 on the F55 for quick turn around work where images won't be graded much and the results are fantastic!)

    All this sounds super duper exciting and the marketing guys at Sony love this kind of stuff, but to put these dynamic range percentage numbers in perspective it means for example that a cinegamma with 460% dynamic range captures brightness levels 5.1 times higher than 90%. 800% captures levels 8.9 times above 90%, and 1300% 14.4 times above 90%.

    Although we know the more levels and detail we have in the highlights region the better, it stands to reason that only specific scenes with specific types of highlights elements are going to benefit from it, and that's if slog is exposed properly in the first place, and then in post it is handled correctly.

    On a bench, in theory or in marketing literature its definitely easy to talk about 14 stops dynamic range, in "real life" it can be difficult to translate into much.
    Dennis Hingsberg


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    #20
    Senior Member macgregor's Avatar
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    Quote Originally Posted by Samuel H View Post
    (edit: I doubt that firmware update will ever come, but here's a more realistic request: right now, recording externally, you get one stop extra in the shadows, but lose one stop in the highlights because something goes wrong and it clips sooner; fix that highlight thing with a firmware update and the a7s will be clearly above any other camera in its price bracket in terms of DR)
    Wait what?


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