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HDR Underwater

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Is anyone producing HDR underwater content?

 

What sort of shots/scenarios do you think would actually benefit from HDR? Usually, we don't have a lot of specular highlights or deep shadows underwater, at least not when shooting balanced light scenes where you blend the ambient light with illumination you bring down.

 

Maybe the reflections off silvery fish?

 

But I'm curious if there is potential from the technology underwater, and if anyone is doing cool things with it.

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Is anyone producing HDR underwater content?

 

What sort of shots/scenarios do you think would actually benefit from HDR? Usually, we don't have a lot of specular highlights or deep shadows underwater, at least not when shooting balanced light scenes where you blend the ambient light with illumination you bring down.

 

Maybe the reflections off silvery fish?

 

But I'm curious if there is potential from the technology underwater, and if anyone is doing cool things with it.

I triggered the HDR question because I consume UHD HDR content

For me HDR BT.2020 has two benefits

1. Wider gamut and colour depth compared to REC709 10 bit

2. Higher value of maximum illumination

 

1. Comes useful even in portrait work but is not specific to HDR though is required for HDR

2. Backlight scenes, caves shot in natural light with black and bright openings, seascapes, sunburst shots

 

All the scenes in 2 you usually try to avoid or expose to avoid burning highlights with HDR you should be able to shoot and reproduce as is

 

Well this is what am hoping for based on the scenes that I see give the largest benefit on land

 

 

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Atomos published a Youtube article in which Jeremy claimed that recording to the Shogun/ Ninja with a Log Profile was HDR.

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Atomos published a Youtube article in which Jeremy claimed that recording to the Shogun/ Ninja with a Log Profile was HDR.

As long as you record with the right colour space and don’t destroy everything using rec.709 this is exactly how it should work plus the monitor is HDR so you can see what you shoot within the limits of the gamma curve of your choice

 

 

 

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Correctly exposed LOG footage is effectively HDR footage when you edit it in a BT2020 wide gamut timeline. Wether its recorded on an Atomos or inside the cam is irrelevant.

 

The Atomos of course gives you 10bit 60p at 4k, which you wo t get internally on any consumer type cam. But that does not change the fact that you got HDR-capable material if you filmed 10bit log.

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Correctly exposed LOG footage is effectively HDR footage when you edit it in a BT2020 wide gamut timeline. Wether its recorded on an Atomos or inside the cam is irrelevant.

 

The Atomos of course gives you 10bit 60p at 4k, which you wo t get internally on any consumer type cam. But that does not change the fact that you got HDR-capable material if you filmed 10bit log.

Not if you recorded REC.709 in that case the gamut is gone and the footage even if it can be made compliant is nkt HDR

 

 

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Sorry interceptor, We are talking LOG. Log is NOT Rec709! If you set your camera to record LOG you are recording HDR capable footage.

 

If you put LOG on a Rec709 timeline - then of course you only get an SDR clip as a result.

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Sorry interceptor, We are talking LOG. Log is NOT Rec709! If you set your camera to record LOG you are recording HDR capable footage.

 

If you put LOG on a Rec709 timeline - then of course you only get an SDR clip as a result.

 

 

Sorry interceptor, We are talking LOG. Log is NOT Rec709! If you set your camera to record LOG you are recording HDR capable footage.

 

If you put LOG on a Rec709 timeline - then of course you only get an SDR clip as a result.

You are right as it appears that the GH5 uses V gamut that is like or wider than Bt.2020

 

I guess the same reason why VLOG looks washed out makes also HLG look weird on a rec709 screen

 

Going back to the ops question you don't need to be shooting HDR effectively either VLOG or HLG are HDR capable or HDR ready I guess the issue is that with both neither the camera LCD nor the recorder screen if you use atomos are HDR so you don't really see what you are shooting

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You are right as it appears that the GH5 uses V gamut that is like or wider than Bt.2020

 

I guess the same reason why VLOG looks washed out makes also HLG look weird on a rec709 screen

 

Going back to the ops question you don't need to be shooting HDR effectively either VLOG or HLG are HDR capable or HDR ready I guess the issue is that with both neither the camera LCD nor the recorder screen if you use atomos are HDR so you don't really see what you are shooting

 

The GH5 has a built-in display LUT for VLOG-L that restores some of the contrast. It's good enough (in conjunction with zebras and the waveform) to expose the footage correctly and get a rough idea of what the contrast range will look like.

 

In terms of where it could produce better results underwater (in terms of dynamic range), I think the backlit scenario is the most common. (I mean, how often are you shooting inside caves with the opening in frame?). This is a scenario I generally try to avoid shooting in 8 bit because the results never look good. Maybe with a log file you would be able to pull decent details in the foreground subjects, but my thinking is you'd need more than the 11-12 stops of dynamic range of the GH5. Maybe with a 14-15 stop cinema camera.

 

For sunburts, it theoretically isn't going to make much of a difference, since the sun is going to be blown out regardless. If you're exposing for the sunburst, the rest of the shot is going to be so many stops underexposed that ever 14 stops of dynamic range isn't going to save it. Usually with photos, you need quite powerful strobes to get nicely balanced sunburst photos.

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So what you are saying is that with the VLOG upgrade you get the option to set the screen in a reasonable way

On the other hand this is free for HLG with the screen help modes assuming you like them as is

I do have caves with the opening in the frames when you exit them more swim through then real deep caves it makes a nice shot

 

 

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Darek,

 

Beautiful!

 

You may want to correct the typo at the end: DRGAON is probably meant to be DRAGON?

 

Tom

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To conclude @dreifish nobody produces HDR because there are almost no options to grade without specialised video hardware

Have spent some time on this and reached some conclusions will do some write up soon

 

 

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I produced 3 episodes for Discovery: Underwater Planet 4K HDR.

HDR trailer:

 

www.dareksepiolo.com

 

Nice.. are these available for streaming online anywhere? Very curious to see the results on a true HDR display.

Edited by dreifish

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That YouTube clip doesn’t trigger an HDR flag on my Tv or on the iphone X

It does look good though!

 

 

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That YouTube clip doesn’t trigger an HDR flag on my Tv or on the iphone X

It does look good though!

 

 

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Correction it does trigger HDR I just could not see it behind the logo

 

 

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Sorry interceptor, We are talking LOG. Log is NOT Rec709! If you set your camera to record LOG you are recording HDR capable footage.

 

If you put LOG on a Rec709 timeline - then of course you only get an SDR clip as a result.

Don't confuse BT2020 with HDR. They are not one and the same.

You can record and or deliver in BT2020 but if you want to deliver HDR then you must set your timeline to monitor and deliver an HDR compliant file.

 

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The requisites for HDR are in REC.2100. BT.2020 is one of the pre-requisites but not the only one.

In DaVinci I have seen that you can produce a file with BT.2020 colour space but without the corresponding transfer function in Final Cut Pro X the two things go together and the program uses the transfer function of source files to decide PQ or HLG.

If you shoot VLOG L on the GH5 you need a LUT to bring it into BT.2100 if you shoot HLG you don’t

In any case from what I am seeing is impossible to properly grade PQ without a reference monitor. HLG is much more forgiving

 

 

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Edited by Interceptor121

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Sorry interceptor, We are talking LOG. Log is NOT Rec709! If you set your camera to record LOG you are recording HDR capable footage.

 

If you put LOG on a Rec709 timeline - then of course you only get an SDR clip as a result.

Coming back to this am looking at VLOG files and they show as REC709 10 bit color sampling full color range

 

The LUT and other adjustments Panasonic provide are for REC709 this makes me think that the GH5 does not use V-Gamut but just REC709 colour space with compressed VLOG gamma. This gives higher dynamic range but narrower color space than HLG option

 

 

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Coming back to this am looking at VLOG files and they show as REC709 10 bit color sampling full color range

 

The LUT and other adjustments Panasonic provide are for REC709 this makes me think that the GH5 does not use V-Gamut but just REC709 colour space with compressed VLOG gamma. This gives higher dynamic range but narrower color space than HLG option

 

 

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There is a white paper out there for the VLOG-L have a look it gives all the details. Can't upload files here or don't know how to.

Edited by Lionfi2s

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There is a white paper out there for the VLOG-L have a look it gives all the details. Can't upload files here or don't know how to.

I have read two documents on panasonic professional

One is the varicam VLOG/VGamut this applies to the varicam cameras that are professional level recorders here there is the full low down on dynamic range color gamut etc

The second is a paper on production considerations for the DVX200 that shares the same processor of the GH4 there is no mention of what the color space is and clearly this implementation of vlog is a castrated version of the varicam

To finish off Panasonic only provides LUTs for REC709 so this looks like the camera uses vlog l gamma to compress within rec709 and then uses the LUT to decompress gamma back into rec709

I have found out a company called mysterybox that provides custom LUT to capture BT.2020 HDR10 using inferno or other monitors

Without that workflow you can only convert to REC709

I suppose using a set of 3 LUTs to accomplish a few more colours is out of reach for your normal underwater production and you might as well use HLG that requires no LUTs

 

 

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I suppose using a set of 3 LUTs to accomplish a few more colours is out of reach for your normal underwater production and you might as well use HLG that requires no LUTs

 

 

Don't forget that HLG is a delivery format! It is build to be used/consumed as-is (news-delivery, broadcast etc..) and as soon as you start grading/correcting it, it will fall apart pretty quickly. Thats what anyone will tell you, and I've actually tried it out myself.

So if you are likely to have post-work to do (as is almost always the case for underwater footage), than VLOG is the better format as it behaves much better - at least in 10bit.

Edited by bubffm

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Don't forget that HLG is a delivery format! It is build to be used/consumed as-is (news-delivery, broadcast etc..) and as soon as you start grading/correcting it, it will fall apart pretty quickly. Thats what anyone will tell you, and I've actually tried it out myself.

So if you are likely to have post-work to do (as is almost always the case for underwater footage), than VLOG is the better format as it behaves much better - at least in 10bit.

Other than not having the right equipment to display it why would it fall apart more than cinelike D? VLOG requires noise reduction in post and therefore for me is not a good option. I tend to do very little color correction in post best case white balance and usually have more interventions on contrast and saturation than colouring

I believe underwater video is closer to broadcasting than studio production so the focus is to get it right in camera as much as possible and do as little as possible later and not the other way around. What kind of issues do you get with HLG? I am aware that there are no monitors to do proper grading but in my land experiments with 150 mbps 422 that is a crap codec I see no major issues other than the inadequacy of my set up my other choice would be cinelike D rec709 but why loose all deep colours at the outset?

 

 

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Its related to the gamma curve that HLG uses. This is probably a good read:

 

http://www.xdcam-user.com/2017/07/what-is-hlg-and-what-is-it-supposed-to-be-used-for/

 

Not just theory, try to grade HLG and youll see it fall apart quickly (as observd on my HLG capable Loewe TV), certainly much quicker than Cinelike D (my favourite for underwater) or LOG.

 

But of course if you dont work on your footage in post, HLG may work for you. Even correctly WBd, I always have quite a few things I want to improve in post.

 

Id also challenge your point that UW stuff is closer to broadcast than to studio. The very inventors of HLG (BBC) have massively graded their BP2 footage in post studio, not rolled it out as shot.

Edited by bubffm

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Its related to the gamma curve that HLG uses. This is probably a good read:

 

http://www.xdcam-user.com/2017/07/what-is-hlg-and-what-is-it-supposed-to-be-used-for/

 

Not just theory, try to grade HLG and youll see it fall apart quickly (as observd on my HLG capable Loewe TV), certainly much quicker than Cinelike D (my favourite for underwater) or LOG.

 

But of course if you dont work on your footage in post, HLG may work for you. Even correctly WBd, I always have quite a few things I want to improve in post.

 

Id also challenge your point that UW stuff is closer to broadcast than to studio. The very inventors of HLG (BBC) have massively graded their BP2 footage in post studio, not rolled it out as shot.

This article refers to the Sony fs5 that as I can read is 8 bits

I see the point about correcting highlights and shadows separately

Still I believe LOG is not for me and rather do cinelike D

I also agre that the fact the camera supports bt2020 does not mean at all it will cover it and in a single shot the GH5 is not likely to exceed 24 bit colors anyway but still capturing 10 is best practice

On the other argument VLOG gamma is even more compressed than HLG and there are HLG grading luts available

 

 

 

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