Monitoring and waveform

[smelni]

I recently visited a set shooting with RED and spent some time with the DIT. He cleared up a lot of things for me but I am confused about 2 areas.

1 - Monitoring - since the image is RAW coming out of the camera there is no DSP on the data. So the output from the HD-SDI cannot be used to judge color on a monitor. In other words if you hook it into a panny BT-lh2600 - you cannot trust the color. You would be applying a "look" or lookup table in the the red application. This presents some issues when we are used to working with HD workflows where you can use the monitor to judge the overall rendition of the scene and sit by the director/client and look at it together. In fact, on this set, the image looked spectacularly clean on the monitor but the color was way way off. Is this correct or I am misinformed/misunderstanding.

2 - Waveform monitor - again because the image is raw and when it is displayed in a monitored the monitor interprets this, an in monitor waveform such as with the BT-LH2600 wouldnt be accurate. I use a waveform monitor religiously when lighting to check for blow outs and distribution of tones/contrast. Is this not possible or reliable with RED?

Anyone who could help me understand this - please do. My brain hurts.

[Graeme Nattress]

There is a "DSP" in the camera - has the same controls as the Red applications RedAlert and RedCine, so when you get the video into post, that metadata recorded on set along with the raw data can re-create that image exactly - only at 4k rather than monitoring resolution.

Graeme

[Matt Uhry]

Hi Gramme,

Can you toggle from the camera between LUT affected image and RAW ? We tried to figure this out, but maybe it was not yet a feature of the build we were using. A button and not menu would be nice for this... And would it be more relevant to look at the Raw image on a WFM?

Matt Uhry
www.mattuhry.com

[Graeme Nattress]

I don't think looking at a raw image is helpful or useful though. What you could do is set the camera to do a minimum of processing, into a rec709 gamma so that it looks "normal" on a monitor. AFAIK, that's what the camera defaults do.

Graeme

[Matt Uhry]

I don't think looking at a raw image is helpful or useful though. What you could do is set the camera to do a minimum of processing, into a rec709 gamma so that it looks "normal" on a monitor. AFAIK, that's what the camera defaults do.

Graeme

It seemed to show some highlights on the monitor and WFM from the HDSDI output that clipped on the WFM yet were bright but OK on the RAW file in RedAlert. Maybe I just need to make "Full Flat LUT" and "Looks Nice LUT" and swap between those two as needed.

Some of this is political too, press a button, show dull flat image "Look this is what we are recording, you can color the crap out of it later" to prevent video-village nags from obsessing about stuff that can be better tweaked elsewhere.

Matt Uhry
www.mattuhry.com

[Stuart English]

Using RED-ONE is a learning curve, although a simple one. It does not work the same way as other RAW cameras, because we anticipated these on-set problems.

That is what is happening - you are not looking at RAW data. You are looking at REC709 video. If you do a White Balance it will be very close to what you see on a "normal" video camera.

Very soon we will enable Look Files that will allow you to enable / disable the RGB image processing parameters i.e. the toggle that you requested.


As for the Waveform monitor - go ahead, use one as you normally would, it won't do any harm.

[jbeale]

The original post sounds like he was looking at a monitor with the camera display settings at some inappropriate levels for whatever reason, and he assumed that it was just the "RAW" output and that the camera had no capability to display a correct white balance, etc. (?)

[Graeme Nattress]

Camera will, as Stuart points out, produce a proper white balance non-raw looking image.

Yes, there's a small 0.4 stop "buffer" between clipping on the output and clipping on the raw data. This is to protect you. By setting the camera exposure controls to -0.4 (Stuart can you confirm this - this is off my knowledge of the math, not the camera), clipping in camera display would be the same as clipping in the raw.

Graeme

[Laco Zamba]

Is false color metering safe tool to prevent clipping always when we will be using different LUTs?

[Stuart English]

Its probably best not to use the term LUTS when discussing RED. Not because its technically inaccurate, but because as soon as we say LUT, people's prior experience with LUT boxes on other cameras comes into play. In practice the RED ONE is placed into a color neutral monitoring path, which is SMPTE / EBU REC709 compatible and your signal level metering reacts to that signal.

If that sounds at all dangerous to you, please just accept that you will also be adjusting as an operator to light levels and the metering too. You have to look at this as a total system which includes light + lens + camera + operator. By eye or meter you will do the correct things.

[Laco Zamba]

I hope that white balancing will not be much important because shooting RAW.
Crucial will be setting exposure and focusing.

[Matt Uhry]

Camera will, as Stuart points out, produce a proper white balance non-raw looking image.

Yes, there's a small 0.4 stop "buffer" between clipping on the output and clipping on the raw data. This is to protect you. By setting the camera exposure controls to -0.4 (Stuart can you confirm this - this is off my knowledge of the math, not the camera), clipping in camera display would be the same as clipping in the raw.

Graeme

Thanks Graeme, that's a credible and useful explanation of what I observed.

Matt Uhry
www.mattuhry.com

[Stuart English]

I hope that white balancing will not be much important because shooting RAW. Crucial will be setting exposure and focusing.

You are correct, setting White Balance is not important, its just a comforting for the operator as it make the monitor outputs ( and EVF ) look color neutral.

[Laco Zamba]

Shanks Stuart. Can be false color metering and magic focus turned on simultaneous while shooting?

Maybe it will be like Allien vs. Predator filtered picture :-)

[RivaiC]

But i think it's quite important for those who wants to design looks on set. We couldn't tell him, hey you can change it later, it's metadata only, despite the fact that we can change it. Because the marketing in HD, people now know the fact that we can see what we want on monitor. So i think it's still important to some people or most people. People don't like the idea of guessing nowadays. Get it right on production at least.

[Stuart English]

Yes we agree, and that's why we have a scheme referred to as a LOOK file. My comment was to stay away from the term LUT, as many people think they know what that is, based on experiences with VIPER etc. But that experience is different on RED. For example on Viper the LUT is external to the camera .....

Yes we can have False Color and Focus Assist active at the same time...

[Laco Zamba]

I think that LOOK file is simmilar to SI-2k approach. Right?

[smelni]

wow - thanks all for the help with this - so if i get this right then:

set the camera at the default/flat look file. Then the hd-sdi out can be used to monitor a pretty much neutral image. You can white balance to help judge the image but it wont affect the data. And a wave form on the hd-sdi out is valid with the actual data being able to hold .4 stop more latitude then the hd-sdi signal will show.

Do I have this all correct?

[smelni]

can i just get confirmation on my last post here so I know I understand this all right, please

thanks

[Brent J. Craig]

Yes, there's a small 0.4 stop "buffer" between clipping on the output and clipping on the raw data. This is to protect you.

I'm not sure the professionals being paid several thousand dollars per day need a camera that 'covers' for them. The reason DPs make what they do is because they know what they are doing.

Perhaps Red needs two branches for firmware development: Wannabees and Professionals

[smelni]

that is an interesting point crewpix

[donatello b]

"Perhaps Red needs two branches for firmware development: Wannabees and Professionals"

IMO a .4 stop buffer Pros' & wannabees will appreciate it ...
and a persons making several thousand a day will appreciated even more then a wannabee !!

[John Hunt]

"Perhaps Red needs two branches for firmware development: Wannabees and Professionals"

IMO a .4 stop buffer Pros' & wannabees will appreciate it ...
and a persons making several thousand a day will appreciated even more then a wannabee !!

Absolutely. Remember riding analog audio levels? We all aimed for "0" VU, but everyone knew you could push it beyond with care...saved me more than a few times, and not in any "wannabee" situations. It's taken me many years of making nearly every mistake once to become a more-humble "pro".

[Graeme Nattress]

I think any professional reading the above would either leave the exposure value at default, or if they decide they wish to see it all, set the exposure to -0.4ev. There's no need for any branching of firmware at all!

Graeme