My PXW-Z90 mini review

[Cliff Totten]

So, I dont know this a fact but....

After working with these profiles for years on Sony cameras, I have a theory. These profile settings are only being applied to an image that was already captured and sent to the image processor as a limited rec709 source.

When you kick these Sony cameras into SLog-2, you are getting an image that was mapped directly from the sensor output. SLog-2 takes the darkest black the sensor sees and the brightest white it sees and maps it from 0-255. So,...SLog-2 is presenting the ENTIRE sensor's possible dynamic range. This is a great thing.

But what about all the rec709 profiles? Its my suspicion that an already clipped and "baked in" gamma curve is presented to the picture profile engine. All we are doing is adding knees and slopes, color phase and black levels....to an image that was already limited at 6 or 7 stops before we even started. We are not given access to the sensor's full dynamic range. These 1 inch-type sensors can see 10 or 11 stops but these non-SLog cine curves seem to dump out 3 or 4 stops at the sensor collection point.

It seems to me that we can tweak an pull and bend and flatten all we want but we are never going to "really" affect what the sensor actually "saw" because that info was already dumped before we got it.

Does that make sense? It would be like me saving a video file in rec709 and you taking that file and flattening it and trying to make SLog out of it. You cant really get much more out of it if the source itself was limited. If my video had clipped white clouds, could you take it into your editor and throw a knee into it to bring my clipped clouds back? No,...all you could do is stretch the white downward and help some of that burned out look. You cant recover what is was never given to you in the first place,

I dont know, this is just a feeling I have had for years and years on many of my Sonys. For sure SLog and HLG ARE taken from the sensor A/D conversion level. In those profiles you truely ARE accessing much more than the typical rec709.

I don't know,...just a thought I have had for years.

[Joachim Claus]

With regard to SLog and REC 709:

Switching the camera to SLog changes the standard Gamma curve from REC 709 to SLog, and bypasses a number of internal video processing, e.g. knee curve, etc. However, It does not change the color space, which will remain REC 709. The color space would only be changed, if it is explicitly set to e.g. REC 2020.

This is the crux with terminology. "REC 709" is used in two ways. First, it defines a color space, and second it defines a gamma curve. As said above, SLog will change the gamma curve, but not the color space.

Joachim

[Paul Anderegg]

When I set my Z90 to HLG/BT2020, and import it into FCPX, it shows as REC709, and throws a warning if I change it to color space override BT2020, says doesn't match the clip.

Paul

[Christopher Young]

The thing with Sony's HLG, ‘Instant HDR’, is that the metadata embedded in the XAVC video file when recording can be read by a supporting TV or monitor and displayed automatically with the correct HDR settings. Hybrid Log-Gamma was specifically developed for broadcast television by the BBC and Japanese broadcaster NHK. The main benefit is that HLG’s native compatibility allows existing broadcast SDR infrastructure to be re-used for 2020, 2024 and 2100 HDR transmission. The HDR encoding will automatically be displayed correctly as HDR when viewed on a TV or monitor that recognizes the HDR 2020, 2024, 2100 sub code data switch. If the TV or monitor cannot see and decode the HDR sub code data switch then the stream will only be displayed as HDR 709.

In other words if you have the color mode on your recording selected as 2020 only HDR display equipment OR NLE software that recognizes the HDR 2020 switch will correctly interpret your footage. If it is recognized as HDR the NLE software would then have to be operating though a graphics chain, e.g. graphics card and monitor that supports HDR to display it as HDR. If the hardware and software don't see the HDR switch then all that will be decoded and displayed from the 2020 recording will be the embedded 709 color space information.

HLG1, HLG2, and HLG3 all use the same gamma curve characteristic. Only the dynamic range and noise suppression characteristics differ. Regardless of whether the 2020 or 709 color mode is selected for the recording the maximum values for the recordings are the same as for SDR as this HDR workflow was designed to be run over SDR transmission systems and infrastructure. HLG1 peak is 87%, HLG2 peak is 95% and HLG3's peak is 100%. Sony's HLG2 being the best optimization between signal dynamic range and the noise floor.

Of course if the recording was color space 2020 then imbedded in that 87% to 100% range is the extra highlight information that will be extracted and displayed by hardware and software that recognizes this HDR sub code data switch and is capable of displaying the extended highlight range.

Paul I would suggest that FCPX doesn't yet have the code to recognize the HDR sub code switch and is only seeing the embedded HDR 709 information. i would think that is why it is flagging you a warning when you try to switch FCPX to 2020 color space.

Well that's how I understand this minefield of HDR as it stands. I may be wrong but I don't think so.

Chris Young
CYV Productions
Sydney

[Paul Anderegg]

Yeah, seems like the "HDR" features of the Z90 will be something I will never play with, as I have absolutely no way of displaying footage...can't even get my Samsung 4K TV to show as HDR...oh well, not what i bought the camera for.

Paul

[Christopher Young]

:))

Chris Young

[Lou Bruno]

I have a new Samsung 55" with HDR. Hidden deep in the menu,


I'll give it a shot in a few weeks....if I only can figure out the proper camera setting. In any event, I am not that crazy with HDR on Netflix and some YT material.

[Mark Watson]

Regarding low light operation:
With camera in auto mode, AGC off, LOW LUX on, the camera will gain up as far as 33dB, shutter speed didn't drop below 1/30.

NightShot mode worked very good, AF was decent.

Mark

[Paul Anderegg]

Unfortunately, AUTO mode invalidates anything other than AUTO WHITE BALNCE. The Z90 does retain PP settings in auto, unlike the X70 and Z150.

Paul