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-   -   Finally got to shoot in XAVC mode (https://www.dvinfo.net/forum/sony-4k-ultra-hd-handhelds/526172-finally-got-shoot-xavc-mode.html)

Paul Anderegg December 22nd, 2014 08:02 AM

Finally got to shoot in XAVC mode
 
Thanks to Catalyst Browse........shot some overnight stories in 1080p60 XAVC, and I can tell you, it is a very noticeable picture quality improvement over AVCHD I have been shooting! I took a few clips from some stories, using new picture profile calibrations as well, and I am very impressed with the quality bump 50Mbps gives.


Mike Buckhout December 22nd, 2014 08:11 AM

Re: Finally got to shoot in XAVC mode
 
Great, but the video says it is unavailable?

Kris Kohuth December 22nd, 2014 09:40 AM

Re: Finally got to shoot in XAVC mode
 
I'm not seeing those abruptly-clipped blobs of highlights that I'm used to seeing from this sensor. The streetlight globes, and even the license plates, haven't gone nuclear as I would have expected.

Is that a function of your profile? Watching zebras when shooting? Or do you think the codec is kicking in?

Thanks (again) for all the samples.

Jeff Harper December 22nd, 2014 10:51 AM

Re: Finally got to shoot in XAVC mode
 
Very nice images, thanks for sharing.

Paul Anderegg December 22nd, 2014 04:52 PM

Re: Finally got to shoot in XAVC mode
 
Yeah, unlike the broadcast cameras that i am used to, this camera clips at 95IRE. Most 3 chip cameras, the big ones, can still give detail all the way to 108-109%. I used to have my zebra set to 100IRE, but just brought it down to 95IRE, because you can see on the LCD, anything above that vanishes into "the blob".

Typically, I dial down 3db (one gain notch) from what looks bright and pretty on the LCD. I am not intentionally underexposing, but the highlight handling on this camera is just not what you get on others, and brighter stuff tends to look less detailed, even if your well within the highlight range.

On the histogram, this camera produces lots of high end 108IRE signal, it's just that your looking at 95-108IRE of "blob", there is nothing usable there. By usable I mean enough detail to dial down below 100IRE and actually want. Anything above 95IRE is about as useful as wet toilet paper.

Will be posting new PP settings soon, these were shot on a couple of new Cinematone 1 settings.

Paul

David Dixon December 24th, 2014 11:52 AM

Re: Finally got to shoot in XAVC mode
 
Paul, that explains some of what I've been seeing. I'm coming from a Canon XF100 where I liked shooting very flat and using post tools (FCPX scopes) to put exposure and saturation and color tweaks where I want them. The XF let me have wide control over all this with no side effects - sort of a Canon log approach. And I like the way the Canon manual includes graphs with curves showing exactly what Knee and Gamma changes do.

But I can't seem to truly do this with the X70. Black Level and Black Gamma work pretty well - I just shoot with everything at maximum stretch - Black level at +15 and Black Gamma at +7, although even this still gives darker shadows than I am really aiming for. (BTW, does the High/Middle/Low Black Gamma Range selection pick a narrow subset of the shadows to be a affected by the Level setting, or does it function almost like a Point selection, sliding up or down the point at which the Level adjustment kicks in??? - I thought it was the latter, but with Level at the +15 setting, a Range setting of Low raises the darkest shadows more than if I set the Range to High, so maybe it's the former...but I digress).

Anyway, the Knee Point and Slope are the ones I still haven't made my peace with. Like Paul says, the highlights are very odd at times. The point settings go down to 75%, but anything below the earlier recommendation of 87.5 can lead to weird strobing and almost posterization, especially if combined with a low Slope as well - anything below -2. I don't really know what I'm talking about here, but it seems like rather than the Knee Point adjustment sliding the exposure curve down, it just throws a cap on it. On the Vectorscope in Browse or FCPX I can see it - there will be a hard line showing clipping of highlights, but it will be at 80IRE - nowhere near what should clip. I'm finding I have to keep the Point at 87.5, or even better, 90, to fully retain the gradations.

So, nobody else may be trying to get a flat, non-final look in camera, but for now (definitely still a work in progress) I'm sticking to Black Level of +15, Black Gamma Range Low and Level +7, Knee Point 90, Knee Slope 0, and using the Histogram (really miss the Waveform Monitor of my XF100) to make sure I rein in those highlights. I also can't decide if I prefer ITU709 or Cine.1 on the Gammas and Color Mode, or even what Zebra level to set. So far I find the Zebra readout a bit inconsistent and puzzling as well.

Paul, I appreciate all the work you've posted on the forum about color. Most of it is over my head, but I will dig into that eventually. For now, the things I've discussed here are a bigger stumbling block for me than the color accuracy. Despite my ongoing adjustment to the X70, I do like the camera and find its image a definite step up from my XF.

Paul Anderegg December 24th, 2014 03:31 PM

Re: Finally got to shoot in XAVC mode
 
I tried to make it so you can put the corrections in, then adjust from there as needed. It was hard enough to do on a scope, so I wanted to get the scopable stuff out of the way and leave the "tuning" from those settings on as eyeballable.

I like adding able to stuff. :-)

If it would help, I can record a single file while switching gamma levels and such while pointing at the center grayscale box on my DSC chart? This would allow you to pull up a waveform monitor on your NLE and watch as the levels change and I call out each setting adjustment. I found MIDDLE to be the best for me, as HIH pulls the 20-30IRE section down about 10IRE, too close to where I want to retain and broadcast my ink black levels for news.

I can do the same with KNEE levels if you wish, I have a live waveform monitor so I am able to correctly set my 100IRE on my DSC chart for better accuracy.

Paul


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