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Re: Difference between two Alexa Mini Cameras
Xiaosu:
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Does each camera have it’s own monitor? The monitors may not be matching. Try A/B’ing the cameras on one monitor or better yet, put both camera pictures up side-by-side on the same monitor. Try switching the camera input top to bottom and bottom to top. See if the problem follows the BNC input. Are you using the internal ND’s. The ND’s may not be matching. Are you using the same firmware build in both cameras? Make sure both cameras have the latest firmware and are matching. Hope this helps, John John Sheeren Film/HD 713-385-7595 Johnsheeren@...
On Thursday, October 1, 2020, 9:58 AM, xax@... wrote:
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Re: Difference between two Alexa Mini Cameras
Andrew Hunter
Hey Xiaosu, That sounds like one of your bodies needs to go back to Arri for recalibration. For any long format work with multiple cameras, I shoot a side by side to verify matching for color and exposure in prep. If they don't, we swap the body. I've seen some mini bodies have 3/4 of a stop difference. Rare but we noticed it for the current season of Kim's Convenience. Sincerely, Andrew Hunter A cam 1st AC - Kim's Convenience S5 Toronto, Canada
On Thu., Oct. 1, 2020, 10:55 , <xax@...> wrote: Dear CML Group,
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Difference between two Alexa Mini Cameras
Could you send me higher-res images? I can pass this on to someone internally for a look.
-Art
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Difference between two Alexa Mini Cameras
xax@...
Dear CML Group,
we are having a problem on set shooting with two Alexa Mini Cameras, both are on the same lens, same settings (WB, CDL, etc), same stop, same LUT, everything is the same, but one camera unfortunately looks completely different than the other! In the Image, on the left side, we have the A Cam on top and the B Cam at the bottom.  I then tried to create a LUT to match the two cameras, as can be seen on the bottom right, which matches the B cam to A cam. It works in this one lighting situation, but in others, it falls apart. This is the first time we are having such a big difference between two Alexa's and are quite puzzled by it to be honest. We are getting another replacement body next week, but in the meantime I am very eager to find out what the reason could be. It would help for future 2 Camera shows, in regards of what to look for (serial numbers?) and how to remedy that problem. Thanks for any advice pointing to a solution, all the best, Xiaosu Han cinematographer, currently based and shooting with FFP2 masks in Vienna, Europe www.stilfabrik.at
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Re: HDR in the real world
David Rasberry
Refinements to grading standards and the HDR firmware in consumer displays that interprets those are certainly welcome. But it does not relieve the necessity of doing at least a basic value scale calibration of the TV to one's own viewing environment. Value distribution in programs, especially through the critical midrange , shouldn't shift dramatically between SDR and HDR material. Most of the desired value differences show in extending the contrast range at the extremes maintaining color, texture and detail into deeper shadows and more subtle shading differences in near whites as well as better micro contrast and color contrast. I bought a new 65" mid-range LG HDR LED TV for the living room last winter in anticipation of the Covid lockdown. It is a typical 300 +/- nit display, not the 1000 -1500 nit range of the high end models. It supports HDR10 and HLG standards but not Dolby. The native black level of the panel is perhaps two stops lighter than the inky blacks of a high end OLED set but it is far superior to the 15 year old 32" LG it replaces and amazingly cost the same price as I paid for the old one. It sits in a dark corner of the room on a 42" high book case to the left of a large picture window that occupies half the wall space. This morning is overcast with outside ambient light levels running about 160-200 FC and the light coming through the window measuring about half that. Two couch side reading lamps are on across the room. Ambient light at the screen surface measures 5+/- FC, which I would say is typical for morning and evening viewing conditions. It can go as high as 15 FC mid afternoon on a bright sunny day. I like LG's because they have easily accessible Expert mode user calibration menus and a built in guided visual calibration routine for basic brightness, contrast ,sharpness, color, and gamma tweaks that works pretty well. The new HDR set added two Expert mode user presets, one for dark room and one for light room conditions. Menu access to the HDR modes was a bit quirky on the new set as one actually has to be viewing HDR material to access them. Initial out of the box viewing experience with HDR programs on the new set was disappointing as Geoff describes, with very dark average scene values and muddy shadows on many programs regardless of which standard viewing mode was selected. The basic guided calibrations didn't help this. I found this test chart online to use for a visual reference: Test chart It maps full data range gray scale values as well as the usual REC709 value range. Ran the chart through Resolve to check and correct it by the scopes and exported a 10bit HLG REC709 conversion to use as a reference for visual calibration. I set HDR black levels, brightness, gamma and contrast to match room viewing conditions and resolve the full data range gray scale values. An important HDR menu adjustment is one that acts like a dynamic range expander to push the maximum range the display is capable of accurately reproducing between panel black level and white clip. Even with this approach it took several rounds over a few days of viewing to get it dialed in to my satisfaction, but now most HDR programming map values as it should and the shifts in DR, grayscale, color refinement, and micro contrast really pop the HDR material compared to SDR without radical and inappropriate value shifts viewing anything from live newscasts to Neflix Ultra HDR streams. Mind you there are still a lot of poorly graded muddy dark program examples out there, but many that look spectacular too. It is even possible to distinguish subtle differences in qualities between digital and film originated material. Some of the recent HDR restorations of films like Coppola's Cotton Club are lovely. Worth giving it a try. David Rasberry
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Re: HDR in the real world
You may want to have a read of this:
https://www.lightspace.lightillusion.com/uhdtv.html We explained the issues with HDR in the real world to Dolby when they first introduced PQ HDR, and that is exactly why they have now added IQ to Dolby Vision - which totally breaks the PQ standard... Steve Light Illusion
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Re: HDR in the real world
"Also, it’s all very well having a domestic monitor in a grading suite but if the suite isn’t lit to domestic levels then it’s pointless." It is like having "Auratones" (or, as we called them in my audio days, "Monotones") in an utterly silent mixing theater! Ken P. (415)279-4184 (mobile)
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Re: HDR in the real world
Roberto Schaefer, ASC, AIC
To respond to Mr. Nagel- Many of the TV set manufacturers are now agreeing to and have already began tp put into their newest sets a "filmmaker's choice" type of setting where the TV will automatically set itself through metadata from the source to the grade and output that the director / dp have decided is the right one as established by their "master" grade. One can only hope that this is built into every TV set from here on in to guarantee (as much as possible due to individuals viewing conditions) that the image is presented on the set as intended by the filmmakers.
-- Roberto Schaefer, ASC, AIC Venice, CA ganzo@... The Key To The Light Is In The Dark
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Re: HDR in the real world
Of course we need standards in grading, I’m not arguing against that. What we need are output transforms that more accurately reflect viewing conditions. On my domestic set I have 2 calibrated options for day or night, for Dolby I have bright and dark. I simply think we should have a few more options including “bloody bright” 😊 Also, it’s all very well having a domestic monitor in a grading suite but if the suite isn’t lit to domestic levels then it’s pointless.
I think we’ve found next Wednesdays discussion topic!
cheers
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Re: HDR in the real world
Mike Nagel
On Fri, Sep 25, 2020 at 07:26 AM, <alister@...> wrote:
Perfect Master for whom?No, your approach is flawed. You have no idea what the "avg viewing environment of the majority of people" is. Matter of fact, you have ZERO idea. Because it is not only a demographic, regional but also a temporal moving target. In other words: you don't know the character attributes of your audience (most importantly vision, as that will change w/ age) but also financially b/c some folks (young or old) will have better TV sets and/or calibrated environment, but you also don't know where on the planet the "majority of people" is that watches your stuff and what their avg viewing environment is. Asia is drastically different than Europe. Always has been, always will be. So even if you buy the current (as in: today) top 10 TV sets, use all of them as client end screen, non-calibrated and find somehow a middle ground where it looks somewhat decent and/or acceptable - you still have ZERO idea which TV settings your audience uses, picture mode etc that will all mess up your compromised "grade". It's impossible to accommodate for all factors here alone. Enter father time: in the future, your audience will watch your content on newer TV sets, not the old, outdated ones that you optimised for, newer sets that will be closer to standards and perform much better. Your content is static, and b/c you compromised it will never look as good as it could have. You can't win this. Your only true chance is to master to known standards on calibrated equipment, THIS is how you position yourself dead in the center and this is also how you achieve logically the least amount of avg distance to your audience, who all watch on different sets and in different environments w/ different settings and variable vision. Mike Nagel Director/Producer L.A.
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Re: HDR in the real world
Video Assist Hungary
When I renovated my flat, I have designed my living room totally around the tv (and the two vintage Tannoys). When it turned out the sweet spot on the sofa (60 degrees from each speaker) is not directly in front of the tv, I designed a rail system where the whole cabinet slides two feet to the left, thus blocking the staircase, but coming to the right place.
I also have a ‘smart home’ where written several scenes controlling the lights, one called TV (lots of lights dimmed but generally not very dark) and Movie, where I actually measured levels to be in the standard. Then I took our calibrator home and set the 65” HDR OLED up properly. Generally, I went a lot of trouble and cost having it exactly right. I wanted the perfect conditions. I don’t think I used Movie more than three times in two years. Almost all movies we watch at the TV setting. If we’re watching tv series or a rom-com we just leave it at normal. The movie setting is so dark you knock your glass over, bathroom breaks have to be programmed and the dog goes in the other room. It’s unusable. Balázs Rozgonyi CEO Video assist hungary
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Re: HDR in the real world
Bob Kertesz
<We> make stuff look nice for the lucky people that do get to viewAKA clients, or Those Who Pay The Bills. Of course we do. Way too many variables in the home, though, and if you dim your lights to view content, that's another one. Incandescents that go down to a very 'yellow candlelight' 2000K, and dimmable retail LEDs whose CRI and spectral rating is always based on not being dimmed affect color and contrast perception. The recessed LEDs in my living room, which aren't bad in those areas when not dimmed, go a consistently very slight pastel green-ish when they are. And I chose those after rejecting almost a dozen that were much worse. At least they're all the same color when full up or dimmed as low as they'll go (the only two states in which they live). -Bob Bob Kertesz BlueScreen LLC Hollywood, California Mostly Retired Engineer, Video Controller, and Live Compositor Extraordinaire. High quality images for almost five decades - whether you've wanted them or not.© * * * * * * * * * *
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HDR in the real world
>Therefore, I would like to turn myself in to whatever authorities have jurisdiction over my near total disregard for viewing conditions.
I bought an HDR TV just before lockdown. I didn’t want to spend a ton of money, but I did want to replace my 12-year-old HD TV with an affordable HDR option. I ended up with a Sony LCD HDR TV.
There’s a table lamp about 6’ to the right of the TV that I turn on at a low level when watching at night. That tends to make the blacks look dark enough that I don’t mind the low-level glow of the backlight in dark scenes. It’s not perfect, but it’s 100x better than what I had.
-Art
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Re: HDR in the real world
alister@...
I’m all for set standards, but the standards should refelect real world application. We are very good in this industry of creating standards that don’t reflect the real world and the way the majority view what we create but make stuff look nice for the lucky people that do get to view content in a perfect viewing room.
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5 nits/5 Lux isn’t dim, 5 nits is pretty dark and not at all representative of any real world typical home viewing environment. Most living spaces are lit above 100 Lux, I can get my living room down to about 15/20 Lux before my dimmable LED’s start flickering, but I rarely go that dark in an evening as I’m likely to break my neck tripping over one of our dark grey dogs. In most countries public spaces that require a dark environment such as galleries are not supposed to be darker than 20 Lux for safety reasons. 5 Nits/5 Lux simply isn’t representative of the vast majority of home viewing environments. So why was 5 Nits chosen? And most of us writing/reading this understand that if we want to get a good viewing experience dimming the lights is necessary. I would suggest that the majority don’t dim their lights to anywhere near to 5 Lux. So why was 5 Lux chosen? Who is the target audience, because it doesn’t seem to be people at home. Has any research been done into how grading for a 5 Lux grading suite impacts real world viewing? Any blind tests with an unbiased audience at home comparing different grades produced under different light levels? Or have we just assumed darker is better? Alister Chapman Cinematographer - DIT - Consultant UK Mobile/Whatsapp +44 7711 152226 Facebook: Alister Chapman Twitter: @stormguy
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Re: HDR in the real world
Mitch Gross
On Sep 25, 2020, at 1:25 PM, Brian Heller <Brianheller1@...> wrote: I’ll get my best man on it. When I care, as in when I settle in to watch a movie, I turn off the lights in the room. Short of what’s reflective from the photons emanating from my screen, I’m at 0.0fc. Anything else, all bets are off. As far as I’m concerned I want to see stuff graded to a dark room and when I don’t care as much I can switch the TV to “vibrant” mode anyway. I know, sacrilege. At least I keep off the damn motion smoothing. Mitch Gross New York
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Re: HDR in the real world
Brian Heller
Since CoVid 19 lockdowns and quarantines, I have become habituated to watching films on whatever TV is handy, especially in the kitchen, for obvious reasons.
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Therefore, I would like to turn myself in to whatever authorities have jurisdiction over my near total disregard for viewing conditions. I also will admit to an occasional glass of wine, which seems to eliminate any of the concerns I used to have about focus, lighting, acting, composition, hair, makeup, sound, continuity, dialogue, etc. Mea culpa, Brian Heller IA 600 DP
On Sep 25, 2020, at 12:37 PM, Bob Kertesz <bob@...> wrote:
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Re: HDR in the real world
Bob Kertesz
All my jokes about having to watch HDR with windows blacked out,Before this devolves into a 100+ post thread about pixels on the head of a pin, as these things inevitably do, anyone else willing to kick in a few dollars or euros to get a "We'd like to get a head-to-toe shot of Geoff in a full burka!" fund going? -Bob Bob Kertesz BlueScreen LLC Hollywood, California Mostly Retired Engineer, Video Controller, and Live Compositor Extraordinaire. High quality images for almost five decades - whether you've wanted them or not.© * * * * * * * * * *
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Re: HDR in the real world
Tobias Wiedmer // Cine Chromatix
I second Kevin’s opinion. Grading for a living room means chasing moving targets, so we definitely need a normed mastering environment. 5 nits as defined dim surround sounds appropriate to me. the problem should be tackled on the distribution side with the choice of a high end colour appearance model, which translates the perception of the image of the mastering suite perfectly into the living rooms, using the environment and maybe the white point as input and some kind of LMSish model under the hood. Curious how Dolby IQ will perform in that matter. But I agree that there is a problem right now.
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just my 2 cents, cheers, Tobi ----------------------------------------------------- Tobias Wiedmer, CSI Lead Colourist / Colour Scientist Cine Chromatix KG Goethestr. 85 10623 Berlin Tel: +49 (0)30.327 805-88 Fax: +49 (0)30.327 805-90 mail@... www.cine-chromatix.de Vertreten durch die Geschäftsführer: Janosch Benz, Ufuk Genc Registergericht: Amtsgericht Berlin-Charlottenburg Registernummer: HRA 39272B ----------------------------------------------------------------------------- P before printing this email, think about the environment
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Re: HDR in the real world
Kevin Shaw
Perfect Master for whom? The perfect Master today is really an archival master that will stand the test of time and captures the creative intent. We then trim it for different audiences -Theatrical, SDR TV, HDR tv, internet sometimes one of them, sometimes many of them I believe this approach is fundamentally flawed as this is not what the most important people, our audience, will see. We don’t make content to satisfy the small numbers that will view it under perfect viewing conditions, we produce content that will look as good as possible in an average viewing environment to the majority of people. This is the way we have always done it and it has worked out well so far. True the content will only look as intended under perfect viewing conditions that’s always been the case and is the driving force behind Filmmaker mode. Very few TVs have ever had anything like a rec 709 mode and so variations to take into account include manufacturer, technology and settings as well as lighting. We deal with that by working in a calibrated environment that could be recreated but usually is not. HDR adds complexity because a 1000 nit master only looks the same on a 1000 nit screen and consumer screens range from about 400 to 800 nits usually. So we have to anticipate tone mapping as well. Only Dolby Vision lets us check the tone map and trim it as needed and only Dolby Vision is the same across all manufacturers. We have to consider that anyone watching HDR is expecting to see more dynamic range, at least some of the time. And as Geoff points out if your TV is already tone mapping down AND you put the lights up the resulting dynamic range perceived by the human eye is small. In some situations I would venture to say negligible. It may seem counter intuitive to grade in a different environment but it is necessary. I apologise for using the word dark in its colloquial rather than its color science sense. But our grading suites are increasingly different to peoples homes. Homes are predominantly 2 technologies (LCD and OLED) which range between 100 and 300 nits for SDR and 400 - 800 nits for HDR with unknown tone mapping, unpredictable local dimming (spatial and temporal) and are rarely calibrated. Our best approach to satisfying such a wide audience is to use predictable technology in a calibrated environment at the highest standards. In about 5-10 years time I expect the capabilities of HDR in the home will more or less match our HDR grading standards today. Thats what happened when we switched from CRT technology in the SDR world. Masters we make today should look just as good when that time come as they do today. Kind regards Kevin Kevin Shaw, CSI kevs@... colorist, instructor and consultant mobile: +44 7921 677 369 skype: kevscolor finalcolor: www.finalcolor.com ICA: www.icolorist.com linkedIn: www.linkedin.com/in/kevscolor ------------------ This message was sent by Kevin Shaw of Finalcolor Ltd. and may contain confidential and/or privileged information. If you are not the addressee or authorised to receive this for the addressee, you must not use, copy, disclose or take any action based on this message or any information herein. If you have received this message in error, please notify the sender immediately by e-mail and delete this e-mail from your system. It is believed, but not warranted, that this e-mail, including any attachments, is virus free. However, you should take full responsibility for virus checking. Thank you for your cooperation. ------------------
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Re: HDR in the real world
Jonathon Sendall
Alistair Chapman wrote "I believe this approach is fundamentally flawed as this is not what the most important people, our audience, will see."
From my experience most good grading suites will grade to exacting standards but also view on something shitty just to see what pops out the other end. The same principal is applied in good sound editing suites. Listen through grade 1 monitors and then play it through downward spiralling quality until you then play it either on an iPhone or small bluetooth speakers etc. Jonathon Sendall DP, London UK
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