HDR capture for the new Apple 4K HDR10

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Helge Tjelta

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HDR capture for the new Apple 4K HDR10

PostTue Sep 12, 2017 7:42 pm

Hi, is the Ursa mini Pro at 15 stops qualified for being used as a HDR camera ?

Wikipedia says 17.6 stops for a HDR display ???

What cameras can actually deliver 17.6 stops?
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Uli Plank

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Re: HDR capture for the new Apple 4K HDR10

PostWed Sep 13, 2017 4:42 am

Pretty much BS, any camera with 15 stops (hardly any camera can do more, even if they claim) is qualified for producing HDR.
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Helge Tjelta

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Re: HDR capture for the new Apple 4K HDR10

PostWed Sep 13, 2017 8:45 am

OK then :)
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timbutt2

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Re: HDR capture for the new Apple 4K HDR10

PostWed Sep 13, 2017 5:04 pm

Netflix approves the URSA Mini 4.6K and URSA Mini Pro 4.6K as a camera for 4K HDR shows. Considering that HDR is capable with the URSA Mini 4.6K cameras, it's more important to worry about the grading monitor. You need a HDR capable grading monitor to grade the footage and ensure that it will look correct.
"Movies are not watched. They are an encounter with a life's experience not your own." - Tim Buttner (timbutt2)

Cameras: URSA Mini 4.6K EF & Cinema Camera 2.5K EF
Computers: iMac 5K (Late 2015) & MacBook Pro Retina 15.4in (Early 2013)
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Howard Roll

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Re: HDR capture for the new Apple 4K HDR10

PostWed Sep 13, 2017 11:24 pm

17.6 stops, man I hope not. That's going to be like staring into a Kino 4bank. I'm going to have to start watching tv with all the lights on.
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Uli Plank

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Re: HDR capture for the new Apple 4K HDR10

PostThu Sep 14, 2017 2:27 am

That's highly theoretical. Imagine going from a 400 Nit display to a 1600 Nit one. That's only two stops!

You can only intensify the brightness to a certain level without needing your own power plant. But of course you can lower the other end by painting your living room black, put in a black carpet und wearing black clothes only, so you can enjoy the black levels of OLED.

Have you ever been to a cinema and seeing an image of the sun blinding you?

Irony mode off…
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rick.lang

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Re: HDR capture for the new Apple 4K HDR10

PostThu Sep 14, 2017 3:32 am

Maybe that article is thinking of the contrast ratio. Marketeers claim the OLED has a 1,000,000:1 contrast ratio. 2 to the power of 18 is only 262,144 or about two stops below that alleged contrast ratio. Just a speculation where that figure comes from.


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Uli Plank

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Re: HDR capture for the new Apple 4K HDR10

PostThu Sep 14, 2017 7:53 am

I'd suppose so too. But nobody has yet invented negative light or a screen without any reflection.
So, one million to one is theoretical too. Sure you can measure that with a probe attached to the screen and shielded from light. But that's not exactly the way we watch movies;-)
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rick.lang

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Re: HDR capture for the new Apple 4K HDR10

PostThu Sep 14, 2017 5:57 pm

Agree, it's likely a silly number.

Still it would be nice at times to capture video with 16 stops as some cameras claim to do. What a blessing most of us have with the most amazing capture device created: our eyes. I understand the eye can typically only see 15 stops in one scene, but can adjust to changing lighting that represents a 30 stop range. Putting our eyes in front of a screen purporting to project more than 17 stops would present a challenge at best for the viewer to take in the entire scene.


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Uli Plank

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Re: HDR capture for the new Apple 4K HDR10

PostFri Sep 15, 2017 1:56 am

Well, it's the human brain that does most of the work. We compose an illusion from scans of the environment. The "automatic exposure" of the eye varies only between a bit over f2 to somewhat over f8. The rest is biochemical adaptation, which is relatively fast going from dark to bright but very slow the other way round.

Consequently, you'll not have those 30 stops at your disposal for one scene, they describe the range between light that hurts and a scene that you may perceive faintly after being exposed to very low light levels for up to 20 minutes (and enough vitamin A at your disposal). A range of 15 stops for one environment seems more realistic.

You can find some very fine reading composed by a fellow filmmaker starting from here:

http://wolfcrow.com/blog/notes-by-dr-op ... ye-part-i/

Warning: not adequate for the scientifically challenged!

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