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Re: HDR question

Nick Shaw
 

On 17 Mar 2018, at 01:34, Seth Marshall via Cml.News <sethmarshall=yahoo.com@...> wrote:

I would like to know how many users here burn in their LUTs in this way. I am so used to delivering Log in scenes with a high dynamic range to protect myself. Do some here always burn it in?
That video is not suggesting you burn in the LUT. Indeed, the Odyssey does not even have the option to do that. The LUT is used for monitoring only. I did another video for CD showing how to apply the print-down LUTs in Resolve.

Regarding my comments about picture rendering, that is not something either a DP or a colourist really needs to concern themselves with an any practical way. I was just pointing out that screen contrast and scene contrast don't relate directly in the way Alistair was suggesting. It is a small insight into the colour science of what is happening in a camera LUT. But in practical terms you don't really need to know why. You just use ACES, or a manufacturer's LUT, or just grade until it "looks right"!

Nick Shaw
Workflow Consultant
Antler Post
U.K.


Re: HDR question

Seth Marshall
 

On Fri, Mar 16, 2018 at 02:58 am, Nick Shaw wrote:
What people often do on the FS7 is to expose one or two stops over, and "print down" for monitoring and post (see this video from Convergent Design).
I would like to know how many users here burn in their LUTs in this way.  I am so used to delivering Log in scenes with a high dynamic range to protect myself.  Do some here always burn it in?
In many situations where a producer doesn't allow time for thoughtful exposure, the thought of burning in the LUT scares me.  If recording raw externally (like the Convergent Design video) is there an added benefit to recording the LUT?

On Fri, Mar 16, 2018 at 08:02 am, Nick Shaw wrote:
To make an image appear perceptually like the scene to a viewer, you do not want the luminance of the screen to be proportional to the luminance of the scene. You require what is referred to as "picture rendering" applied. This is the function of the RRT in the ACES block diagram, or the 1.2 "system gamma" of traditional video, to give two examples.
Nick, forgive me but could you expand on this more?  Is this more of a colorist thing that doesn't apply so much to operators?
--
S e t h  M a r s h a l l
www.sethmarshall.com


Re: HDR question

Nick Shaw
 

On 16 Mar 2018, at 13:19, alister@... wrote:

Nick, could you enlighten me as to how the contrast ratio of a display is different to the contrast ratio of a scene, surely a ratio is a ratio, if a screen can show 10:1 and a scene is 10:1 are these ratios not the same?

A scene and display contrast ratio of e.g. 10:1 may be numerically the same, but they are not perceptually the same, because there is a difference in both the absolute luminance and the viewing environment.

To make an image appear perceptually like the scene to a viewer, you do not want the luminance of the screen to be proportional to the luminance of the scene. You require what is referred to as "picture rendering" applied. This is the function of the RRT in the ACES block diagram, or the 1.2 "system gamma" of traditional video, to give two examples.

Nick Shaw
Workflow Consultant
Antler Post
Suite 87
30 Red Lion Street
Richmond
Surrey TW9 1RB
UK

+44 (0)7778 217 555


Re: HDR question

alister@...
 

It doesn't mean anything to say 1000 Nits "is 10 stops". Stops are relative. 1000 Nits is about 10 stops more than 1 Nit, but 1 Nit has no special significance. SDR displays go much darker than that, and HDR ones more so. Also screen contrast ratios and scene contrast ratios are not the same thing.

Nick, could you enlighten me as to how the contrast ratio of a display is different to the contrast ratio of a scene, surely a ratio is a ratio, if a screen can show 10:1 and a scene is 10:1 are these ratios not the same?

Alister Chapman

DoP - Stereographer
UK Mobile +44 7711 152226
US Mobile +1(216)298-1977


www.xdcam-user.com    1.5 million hits, 100,000 visits from over 45,000 unique visitors every month!  Film and Video production techniques, reviews and news.

















On 16 Mar 2018, at 12:37, Nick Shaw <nick@...> wrote:

On 16 Mar 2018, at 11:38, alister@... wrote:

Most real world HDR productions target 1000 to 1500 NITS for the final output, which is around 9 to 10 stops.

It doesn't mean anything to say 1000 Nits "is 10 stops". Stops are relative. 1000 Nits is about 10 stops more than 1 Nit, but 1 Nit has no special significance. SDR displays go much darker than that, and HDR ones more so. Also screen contrast ratios and scene contrast ratios are not the same thing.

But I agree with your point that pushing the exposure too far one way or the other, to protect either highlights or shadows can be a bad idea.

Nick Shaw
Workflow Consultant
Antler Post
Suite 87
30 Red Lion Street
Richmond
Surrey TW9 1RB
UK

+44 (0)7778 217 555



Re: HDR question

Nick Shaw
 

On 16 Mar 2018, at 11:38, alister@... wrote:

Most real world HDR productions target 1000 to 1500 NITS for the final output, which is around 9 to 10 stops.

It doesn't mean anything to say 1000 Nits "is 10 stops". Stops are relative. 1000 Nits is about 10 stops more than 1 Nit, but 1 Nit has no special significance. SDR displays go much darker than that, and HDR ones more so. Also screen contrast ratios and scene contrast ratios are not the same thing.

But I agree with your point that pushing the exposure too far one way or the other, to protect either highlights or shadows can be a bad idea.

Nick Shaw
Workflow Consultant
Antler Post
Suite 87
30 Red Lion Street
Richmond
Surrey TW9 1RB
UK

+44 (0)7778 217 555


Re: HDR question

alister@...
 


What people often do on the FS7 is to expose one or two stops over, and "print down" for monitoring and post (see this video from Convergent Design).

While this is a useful approach to reduce shadow noise, you are doing so at the expense of highlight latitude. If this approach has been taken, it is more likely that windows and practicals may be blown out, unless care was taken not to. And as Kevin says, if something is blown out in the rushes, it can be hard to make it look good in HDR.

But HDR isn’t just about highlights, it’s also about screens that can show the shadow range better, perhaps with better shadow contrast and this means noise can be more problematic in HDR than SDR as it is reproduced better. So the trick is to getting the right balance so that the crucial and all important mid range is exposed well.  It is a mistake to just look at the highlights and shoot avoiding clipping if this results in a compromised shadow or mid range, likewise it wouldn’t be good to shoot super bright for great shadows if that kills the highlights. You need to find the right balance and not be constantly obsessing over highlight clipping or excess noise, you need to find the sweet spot for the camera you are using, and this normally means getting the mid range right, just as you would in SDR. 

Most current HDR consumer displays struggle to achieve 1000 NIT’s and even if they do, this will only be over very small parts of the screen, so often limited to specular highlights or other “shiny bits”. If these are clipped no one is going to notice as that’s how they tend to look in the real world. Most real world HDR productions target 1000 to 1500 NITS for the final output, which is around 9 to 10 stops. So with most log cameras capable of capturing at least 12 useable stops maybe a touch more, there is still some exposure wriggle room. So if you feel that shooting at the equivalent of 1000 or 800ISO on an FS7 (+1 stop over base) helps with noise then I would continue to shoot that way as noise in the mid range, which makes up the majority of most images, will be a much more noticeable artefact than a few small clipped specular highlights that no current HDR screen can show correctly anyway. If you have a large, bright window in the shot then no HDR TV or monitor is going to deal with this well as it will hit the power limits of the display so it can’t be reproduced super bright and the brightness will be throttled back according to the displays power limitations and the MaxFall and MaxCLL metadata in the final material. So the key to good HDR is no different to good SDR, control the contrast in the scene, avoid extreme highlights and expose well so that you don’t deliver an excessively noisy file to post. 


Alister Chapman

DoP - Stereographer
UK Mobile +44 7711 152226
US Mobile +1(216)298-1977


www.xdcam-user.com    1.5 million hits, 100,000 visits from over 45,000 unique visitors every month!  Film and Video production techniques, reviews and news.



Re: HDR question

Nick Shaw
 

On 15 Mar 2018, at 20:59, Kevin Shaw <kevs@...> wrote:

…it has enough dynamic range for decent HDR, but as James says there is not much latitude at 1000 nits or higher

What people often do on the FS7 is to expose one or two stops over, and "print down" for monitoring and post (see this video from Convergent Design).

While this is a useful approach to reduce shadow noise, you are doing so at the expense of highlight latitude. If this approach has been taken, it is more likely that windows and practicals may be blown out, unless care was taken not to. And as Kevin says, if something is blown out in the rushes, it can be hard to make it look good in HDR.

Nick Shaw
Workflow Consultant
Antler Post
Suite 87
30 Red Lion Street
Richmond
Surrey TW9 1RB
UK

+44 (0)7778 217 555


Re: HDR question

Kevin Shaw
 

Hi Jean Marc

>I have shot a doc on a FS7 in XAVC-I / Slog. It is now being sold to NHK Japan and they are asking if it was shot in HDR.

James gave a great answer and i agree with everything he says. 
I have some additional thoughts on what they may be asking, but just guessing - I have no experience with NHK. (I am a colorist)

First - yes FS7 is HDR compatible, it has enough dynamic range for decent HDR, but as James says there is not much latitude at 1000 nits or higher
Yes - Slog is a valid HDR source. In fact Sony demo a very viable color managed workflow where everything stays slog until the final export

Now the less clear areas. 
Working on HDR and having worked with broadcasters and post houses that work with broadcasters, it is generally agreed that lighting ratios and creative decision in production would ideally be different for HDR planned productions. This is especially true for example if you like to rely on the limits of BT709 and shoot blown out windows, or have practical lights in shot. Even shooting into the sun (way more than 1000 nits!) is a problem. All these things require a lot more work in the grade. So whilst the source media is technically HDR ready, creatively it may need a lot of tweaking. Unless you were asked to deliver HDR it is unlikely that you metered or monitored the extended range or allowed for the changed perception increased brightness and highlight detail might bring.

As James said they may just be asking if there is any clipping in the source media - clipping is hard to sell in HDR deliverables. It usually involves tricky color  grading. Dont think just about bright whites either. Neon lights and bright colors in sunlight may clip in a single color channel. In BT709 we expect them to desaturate, but in HDR we do not.

If the program was post produced in ACES or another color managed workflow, your camera dynamic range has been protected. But if it was just graded and finished as straight BT709, a trim to get HDR might produce disappointing results. They would have to re-conform and re-grade. Or they might ask for the colorist project to work from. Given they only asked if it was shot HDR this seems less likely to be the case but it is worth bearing in mind. 

Finishing HDR and delivering SDR does not have the same limitations, and may actually give a better BT709 version

I dont think they are asking if it was shot HLG. 

Best 
Kevin

Kevin Shaw, CSI :
colorist, instructor and consultant
t +44 7921. 677  369 
e
 kevs@...

finalcolor: www.finalcolor.com  ICA:          www.icolorist.com      
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Re: HDR question

James Barber
 

If you haven't drastically over or underexposed anything, the FS7 in S-Log and the 10-bit codecs definitely give you enough dynamic range to grade in HDR, but not huge grading latitude. Think of grading 8-bit footage for 8-bit playout: it works, but it doesn't let one grade aggressively. 12-bit or higher codecs are best for HDR grading, as it's a 10-bit out. But definitely doable, especially as HDR should mostly just be regular light levels from IRE 0-100, and bright brights from 100-1000+.

Big things for HDR grading in terms of exposure is as little clipping as possible so there can be detail in those highlights, and as much bit depth as possible for colour information in those extreme gradients.

Not many cameras record to any form of HDR natively. The ones that do will record in HLG (Hybrid Log Gamma) and Rec2020 colour space. But crucially, they don't actually record more data than log at the same bitrate – it's just a different gamma curve. Very few cameras record a big enough gamut to actually make good use of the Rec2020 colour space yet (F65 for instance).

That said, HLG is a sort of 'broadcast' standard for HDR that is being pushed for live TV, so NHK might want stuff shot in HLG (Hybrid Log Gamma) to reduce post time. Same how some places currently prefer Rec709 footage rather than Log.

I would say something like "the dynamic range of the recorded footage is HDR compatible when graded, but has been shot in Log format to preserve the maximum range of light and shadow".

Hope that 2cents helps.

James I. Barber
Director/DoP/Editor
London

On 15 March 2018 at 12:21, jmselva <jmselva@...> wrote:
Hi all.

I have shot a doc on a FS7 in XAVC-I / Slog.
It is now being sold to NHK Japan and they are asking if it was shot in
HDR.
Now, being that all modern cameras are HDR capable with they 13+ stops
latitude
and that it is merely a post decision to do or not a HDR version, I find
the question odd.

But I do have a question though : does the XAVC-I codec and Slog limit
in any way the possibility to do a HDR version after the fact ?

Thanks in advance.
Jean Marc Selva, DOP, Paris.



HDR question

jmselva
 

Hi all.

I have shot a doc on a FS7 in XAVC-I / Slog.
It is now being sold to NHK Japan and they are asking if it was shot in
HDR.
Now, being that all modern cameras are HDR capable with they 13+ stops
latitude
and that it is merely a post decision to do or not a HDR version, I find
the question odd.

But I do have a question though : does the XAVC-I codec and Slog limit
in any way the possibility to do a HDR version after the fact ?

Thanks in advance.
Jean Marc Selva, DOP, Paris.


Re: Sony VENICE camera - word on the street

Jonathon Sendall
 

Sorry, double negative "I would not have said the image wasn't "Sony like". The image was NOT "Sony like".

Jonathon Sendall
DP, London


Re: Sony VENICE camera - word on the street

Jonathon Sendall
 

Just finished a shoot on Phantom 4K Flex at ISO 800 and 640. Not a massive problem but it was studio.

Saw the Venice at the CVP stand at BSC. The camera was pointed at some people sitting in at the central cafe and I must say the image on the 4K monitor looked really nice straight out the camera considering the "scene" was unlit. Colours were subtle and the blacks detailed but smooth. Of course this was a grand scientific method of mine, using my eyes. The monitor could have been fed through a LUT, I'm not sure but the take away is that I would not have said the image wasn't "Sony like" and you can take that to mean anything you like. I just liked it and would love to use it on something.

Jonathon Sendall
DP, London


Re: Sony VENICE camera - word on the street

Noel Sterrett
 

On 02/05/2018 12:03 AM, Art Adams wrote:
... so many missing features?
Sony released a limited feature version of the F5/55 in 2013. They included a "roadmap" of what was to come -- for FREE.  I had my doubts. But in the five years that have followed, they delivered everything promised and much more.

Frankly, I've shot movies using fewer features than the F5/55 had then, and Venice has now.

Cheers.

Noel Sterrett
Admit One Pictures


Re: Sony VENICE camera - word on the street

Pawel Achtel, ACS
 

Ø  The ND system, though... I don't know why everyone isn't doing this. It's brilliant.

 

Hey Art,

 

There is no one and fast answer to this. Yes, rear filtering is convenient in most uses, however this requires extra glass at the rear of the lens. This can (sometimes severely) affect performance of certain lenses, particularly with short exit pupil distance. The extra glass can cause image plane curvature resulting loss of contrast.  

 

Roger Cicala published a series of articles on this subject a few years ago. Excellent reading, as usual. Here is a link to one of them:

 

https://www.lensrentals.com/blog/2014/07/sensor-stack-thickness-part-iii-the-summary/

 

I would certainly prefer to have rear ND system as an option.

 

Kind Regards,

 

Pawel Achtel ACS B.Eng.(Hons) M.Sc.

director of photography

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

Facebook: facebook.com/PawelAchtel

Twitter: twitter.com/PawelAchtel

Skype: Pawel.Achtel

 

_._,_._,_


Re: Sony VENICE camera - word on the street

Geoff Boyle
 

Err Art, don’t you always set the Alexa to ISO 400?

 

Having shot with ISO 500 film for a very long time I’m fine with this.

 

Maybe Sony decided the rate it at it’s best noise rating rather than make a marketing point.

 

Cheers

 

Geoff

Sysadmin

 

From: cml-raw-log-hdr@... [mailto:cml-raw-log-hdr@...] On Behalf Of Art Adams
Sent: Monday, 5 February 2018 02:22
To: cml-raw-log-hdr@...
Subject: Re: [raw-log-hdr] Sony VENICE camera - word on the street

 

>(that comes with the Firmware 2.0 in August) and we need a fair bit of that.)

 

That's the part that baffles me. Releasing a camera when major features are six months away seems like an odd marketing move.

 

The ISO 500 native sensitivity seems problematic as well.

The ND system, though... I don't know why everyone isn't doing this. It's brilliant.

 

--

Art Adams

Director of Photography

San Francisco Bay Area

 


Re: Sony VENICE camera - word on the street

Argyris_Theos_cml
 

Mako nailed it

No need to add anything

 

Argyris Theos, gsc

DoP

tel. +30 6944 725 315

skype: Argyris.Theos

www.vimeo.com/argyristheos


Re: Sony VENICE camera - word on the street

Art Adams <art.cml.only@...>
 

This seems like an awful lot of key features to be missing for six months. No 25p in full frame? No false color? No high frame rates? Eventual *partial* remote control? Does anyone have any idea how many people are going to jump on this right away with so many missing features?

It feels like they baked a cake that's raw on the inside and instead of letting it bake a bit longer they're letting us have it now—but it has to sit in a warm room for six months and we'll have to settle for licking the frosting in the meantime.

--
Art Adams
Director of Photography
San Francisco Bay Area


Re: Sony VENICE camera - word on the street

Mako Koiwai <mako1foto@...>
 

On Feb 4, 2018, at 17:22, Art Adams <art.cml.only@...> wrote:

(that comes with the Firmware 2.0 in August) and we need a fair bit of that.)
That's the part that baffles me. Releasing a camera when major features are six months away seems like an odd marketing move.

******

What!

RED started that and everyone else had to follow, so as not to lose potential customers.

Arri certainly followed suit and of course even made their customers spend more for Licenses to use some of those features.





makofoto, s. pasadena, ca


Re: Sony VENICE camera - word on the street

Argyris_Theos_cml
 

We on the GSC had a quick look (not a real test) at the Venice. We will post on our experience soon.

Meanwhile, the Venice will definitely be a dual ISO camera

Also false color will be incorporated from v2.0. This was a feature we missed in the preproduction camera we saw.

High frame rate will be a future add on.

Here is the roadmap to the updates, as communicated to me

 

 

1) SHIPPING

The first units will be shipped from Japan early next week. We expect that the first units will be at our dealers/ customers around Mid/ 3rd week of Feb.

 

 

2) NEW FEATURES & UPDATES

                1) We will add 25p in Full Frame recording from V2. This is very important for European productions as 25p is the man framerate for Commercials & TV productions

                2) False Colour will be available in V2 instead of V3

                3) Partial Camera Remote via wired LAN connection from V2 onwards. This includes the possibility to remotely Start/Stop Record, change ND filter, Shutter, FPS or EI and the Assign Buttons.

                4) DUAL BASE ISO from V2: This is a complete new feature which will add a second High ISO value next to the Base ISO of 500. The second ISO is 2500. To add ISO 2500 as 2nd BASE ISO gives customers to switch between these two depending on the shooting scenes.

                                ISO 500: Ideal for outside and day scenes

                               ISO 2500: Ideal for night/ dark scenes

With ISO 2500 we will have much lower noise. Also Anamorphic lenses are slower compared to spherical lenses so we can avoid Noise with this feature as well.

Last but not least we can keep our superb latitude of 15+ stops and customer can shoot with ISO 800 when they wish. Just combine ISO2500 and add internal ND filter.

                For example: Set ISO2500 Mode à Change to 3200EI à Add 0.6 ND filter à Camera will be like ISO800               

 

All details about the new features can be found online:

https://www.sony.co.uk/pro/article/broadcast-products-venice-firmware-roadmap

 

3) HFR Support

The recording of higher frame rates is currently under development and will be implemented at a later date.

               

 

4) MENU SIMULATOR

The menu simulator can be found here and works with Tablets and PC/Mac.

https://www.sony.net/Products/Cinematography/Venice/

 

5) WORKFLOW/ POSTPRPODUCTION

The following partners have already released their newest Versions. With others like Adobe or Avid we are in close communication.

 

-          BlackMagic Design – DaVinci Resolve 14.3

-          Filmlight – Baselight 5.0

-          Assimilate – Scratch

 

Also our own RAW Viewer has been updated to V3.0 to Support VENICE files. Please download from this link.

https://www.sonycreativesoftware.com/RAWVIEWER

 

Disclaimer: I am a Sony ICE, though I have not served as such for some time

 

Best

 

Argyris Theos, gsc

DoP

tel. +30 6944 725 315

skype: Argyris.Theos

www.vimeo.com/argyristheos

 


Re: Sony VENICE camera - word on the street

Kris Denton
 

Bloody spell check...

There is an update that will have a dual ISO of 500 and 2500.

Kris Denton
DP
LA

On Feb 4, 2018, at 7:59 PM, Kris Denton <krisdenton@...> wrote:

There is in apparent that it will have dual ISO 500 and 2500

Kris Denton
DP
LA



On Feb 4, 2018, at 5:22 PM, Art Adams <art.cml.only@...> wrote:

The ISO 500 native sensitivity seems problematic as well.

1861 - 1880 of 1984