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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Exposure 101...

Patrick Tresch said:
Very interesting Antoine.

REC709 should be banned!

It's wothless for proxies and for monitoring on set. The colors are awfull!

If we have to decide on exposure with the LCD, like Jim suggested, we should have a "close to reality" color space wich is usable for reference with the director, make-up artist and crew...

USE REDSPACE or build another tool that could fine tune the look in camera to use the same contrast/color rendition from shooting to the editing room.

Thanks.

Pat
Click to expand...

Hi Patrick,

I shoot with REDSPACE ISO 250, but i often edit in REC709 ISO 320 and adjust the curve.
I use REDSPACE ISO 250 in camera just because it places the midtones at about the same levels as REC 709 ISO 320 "AND" the whites very close to RAW. I'd call it a quick/safe setting.

I was just tired to constantly toggle between false color and all these (good) metering modes.
I must admit i am not a big fan of always expose to the right.
I prefer a more natural "center" histogram if the scene is lit normally.
Easier for me to achieve a more natural look.
If a scene is very bright, then i'll expose to the right, again, for a more natural/faithfull look.

Maybe i've been just lucky with this method, but then i'm always lucky!

Cheers!
Antoine
 
Axel Mertes said:
2. Forget ALL the ASA/ISO manipulated outputs.

Thats for customers for "video village" applications. Don't care if it doesn't look perfect as long as you are sure the exposure is right (-> RAW).

3. Take care of your framing. Use the RAW monochrome mode if possible, to avoid being disturbed by color interpretations of RAW mode, and to see a brilliant sharpness.

Thats why I also recommend the monochrome mode for framing. Color is the job of the colorist, lateron. We strictly prefer grading "sensor wise", ie. mostly ignoring the ASA/ISO alterations and keep the data as straight "RAW" as possible. This is a strict film workflow. With film I would have had a film scanner sending me simply "full range DPX files". That is what I want. That is what RED ONE makes so wonderful (IMHO).

Axel
Click to expand...


Axel, you do forgot that the interpretation of a look is not only for fun for the video village. They are other departements who needs to see what are the intentions of the DoP as for make-up, settings (décors)... With the film approach you would have made some tests until the print. Today digital technology tends to shorten this step. Therefore having an accurate way of monitoring and communicating with the crew is critical.

The "do it in post" approach is another culture that is valid but not my way of doing things. Choices to color have to be made on set, as for Colors and contrast also participate to the framing choices.

We do not shoot for a well exposed CMO but choose how to expose a picture.

Hope my english was not too bad... :)


Patrick
 
Another vote for all meters using raw data!

I treat exposure on the RED like digital audio recording: get as much signal as possible without clipping (at least, not the areas you want to retain detail in.) Audio recording uses dBFS scales, or "decibels relative to full scale" to convey that information. I think all the meters on the RED should work the same way, and all we really should care about is the raw data that's actually being recorded.

My own approach to exposing with the RED is to start at 320 ISO and get as much exposure as possible without clipping the highlights I want to retain detail in. It's your basic ETTR approach.

If I'm shooting a scene with low dynamic range, that results in everything bunched up to the right and looking overexposed. I know that I have a good signal level in raw, it just looks bad in the monitors. So, I lower the ISO on the camera until it looks good. The exposure is the same, the raw data being recorded is the same, but I've changed the metadata to get a better looking output on my monitors, and in my proxies.

To me, that's exactly the same as shooting ETTR with a DSLR, and then lowering the exposure in my raw processing software later. I just get to do it in-camera, because ISO is just metadata on the RED, not a change in sensor amplification as on DSLRs.
 
Patrick Tresch said:
Axel, you do forgot that the interpretation of a look is not only for fun for the video village. They are other departements who needs to see what are the intentions of the DoP as for make-up, settings (décors)... With the film approach you would have made some tests until the print. Today digital technology tends to shorten this step. Therefore having an accurate way of monitoring and communicating with the crew is critical.

The "do it in post" approach is another culture that is valid but not my way of doing things. Choices to color have to be made on set, as for Colors and contrast also participate to the framing choices.

We do not shoot for a well exposed CMO but choose how to expose a picture.

Hope my english was not too bad... :)


Patrick
Click to expand...

Hi Patrick,

your english is just fine (as far as I can tell), but switching to german here would exclude so many...

Well, I agree that making nice & correct ASA / ISO settings etc. on set to have a pretty meaningful approach of the desired final look is not a bad thing to have,

BUT

no single colorist over here cares about that as it means "loosing information first hand" when importing the material. As soon as you start interpreting the footage in bulk conversion via RED SDK and enabled using the clips stored metadata, you may always result in clipped and missing data, which is just essential in post.

I am in no way someone who proposes "fix it in the post". Who knows me can assure you that we try to fix everything on set instead, to keep post straight and with best results.

All I recommend is that poeple should concentrate on getting the right data captured. I know to many DOPs and projects where time and schedule do not allow to adjust perfectly a look on set, that can be communicated throughout a post pipeline. In fact, most DOPs expect to visit the grading session and adjust color there. If they do so from HD CAM tape or the like they are usually f*cked up in many situtations. The same rule applies when data gets processed with non-perfect ISO / ASA / WB etc. settings in RED SDK. All the perfect RAW footage may go bad, by trying to adjust a "look". IMHO thats part of the team DOP and colorist as typically last stage in post, sometimes earlier.

AFAIK the looks do not yet work in RED ONE, do they?

Honestly, I really don't care what people adjusted during shooting RED footage. When we receive it, we will use in 9 out of 10 projects just the RAW data and grade from there, for the additional freedom and quality we will get.

Its the same difference as shooting on film and telecine'ing to HD CAM or to scan to DPX. The latter will always be better in the results if done right.

Then again, the better the DOP adjusted the coloring of the scene on set (that means setting lights, filtering etc., not adjusting camera to alter sensor data) the less we have to fix in post. Its that simple. Using REDs video out for previewing color is nothing bad at all. But just relying on this to say "I've done a good job" might be very misleading. You can adjust wonderful images on set via monitoring an LCD, EVF etc. but may find in post that some things went really wrong. And these can usually not be fixed anymore.

Regards,
Axel
 
While we're at it, could we please have some sort of indication in the VF/LCD of which LUT is currently applied to the image (RAW, REC709 or REDSPACE) ?
Most of the time it's pretty obvious, but not always...
 
I agree- all meters RAW and a colorspace setting indication in the viewfinder/LCD.
 
For me its a combination of all the instruments that gives one an overall picture of exposure. I would love the RAW meters OPTION (possible?). It would help eliminate some of the guessing. Sometimes its kind of like the displays of some DSLRs that show clipping on the displayed image but you are actually look at a jpeg ref. rather than your true exposer. I say option because I think it is also a good idea to to have the flexibility to see where your exposure lies within the restricted parameters of a particular look or color space.

I also agree with a false color option that is a quicker simpler view. Highlights within a stop or 2 and underexposure within a stop or 2. Sometimes when we are moving fast with a small crew we are adjusting lights very quickly and this would allow us a simpler look to get us in the ballpark quickly.

Buy the way, I love having all the options you've given us because a I use each and every one of them at one point or another.
 
ibloom said:
Well,

All meters to raw yes but.... it's great to know you have that highlight detail in situations you can't control, like sunlit exteriors but.... it's better to light for a particular LUT in be within its confines when you go into color correction. Retrieving highlights isn't always easy or pleasing even in a raw CCer like Scratch.

So, all meters to RAW yes... but... a clear indication of where the exposure lies with regards to the current LUT. On a histogram I can imagine vertical bars that show where clipping will occur in the processed image for example. On the stop lights maybe an open circle for clipping the LUT and a closed one for clipping the raw.

IBloom
Click to expand...

Ooooo. I put all my votes here.
Peace,

-Harry
 
From this thread, I've learned what ETTR means, but can someone clarify what is meant by "Shoot a thick negative or Thick Histogram" ?

The only definition I found for "thick" in this context pertains to how much light gets through, but I'm not sure I fully get it.

thanks
 
I would like for the stop lights to be RAW as well.
 
False colour is a revolutionary idea that AFAIK is pretty unique to Red - it's very handy indeed...but Red should be putting all of their precious time into implementing this phenomenal tool into it being accurate in RAW view!!

Some of the other tools like the traffic lights (if they were RAW) or the RAW rainbow colour meter are good, very rough guides but they aren't particularly accurate in the sense that they may be misled by specular highlights that you might not care about. A definitive RAW false colour what-you-see-is-exactly-what's-going-down-in-the-RAW-world would not only be immensely useful but also unique (AFAIK).
 
Denis Haineault said:
From this thread, I've learned what ETTR means, but can someone clarify what is meant by "Shoot a thick negative or Thick Histogram" ?

The only definition I found for "thick" in this context pertains to how much light gets through, but I'm not sure I fully get it.

thanks
Click to expand...

I believe by a "thick" exposure they mean to light in a way that you fill up the histogram from the blacks to the whites, thus ensuring that you have used the whole range of the sensor.
 
another related request

another related request

Hello,

Right now all histograms and traffic lights refers to all the data from the sensor including the look around area.

I don't know if this is possible with the RED ONE but having histograms showing only the recorded frame data or even better taking into account the custom framing format enabled on the EVF (1.85...) would be great.

And yes to real RAW for histograms, traffic lights false color, and display current colorspace mode on screen.

Mikael Lubtchansky
 
I am confused, are "stop lights" the same as "traffic lights"? All I mostly concerned with the RGB histogram and I thought it was referred to as '"traffic lights"... :blushing:
 
ibloom said:
Well,

All meters to raw yes but.... it's great to know you have that highlight detail in situations you can't control, like sunlit exteriors but.... it's better to light for a particular LUT in be within its confines when you go into color correction. Retrieving highlights isn't always easy or pleasing even in a raw CCer like Scratch.

So, all meters to RAW yes... but... a clear indication of where the exposure lies with regards to the current LUT. On a histogram I can imagine vertical bars that show where clipping will occur in the processed image for example. On the stop lights maybe an open circle for clipping the LUT and a closed one for clipping the raw.

IBloom
Click to expand...

Agreed, as much info at a glance is whats needed. being able to see quickly overall RAW info on histogram as well as Colorspace (LUT) boundaries would be amazing so you could make quick decisions on the fly even and have all that info at your fingertips (eyelids?)
 
Mark Phelan said:
Oh, and thanks for giving us the option to use different methods.
Click to expand...

Amen to that! I usually go by the histogram, the color bar and zebras. Now that Jim and Stewart have explained how to use the shadow zebras, I will feel a lot more comfortable playing in the dark.
 
mikael said:
Hello,

Right now all histograms and traffic lights refers to all the data from the sensor including the look around area.

I don't know if this is possible with the RED ONE but having histograms showing only the recorded frame data or even better taking into account the custom framing format enabled on the EVF (1.85...) would be great.

And yes to real RAW for histograms, traffic lights false color, and display current colorspace mode on screen.

Mikael Lubtchansky
Click to expand...



I find this a very interesting and important point, which Mikael brought up here!

Double thumbs up from here for this one, this needs to be looked at, definetly. Sorry if exposing it large and bold feels inapropriate to some, but I wanted to make sure Mikael's finding isn't missed in the usual wave of forum replies.

I also like Ian's idea of showing both, the RAW ample and an RGB ample.

I guess we have to think about how exactly they are seperated visually.

My vote would be to measure really only the area that is going to be stored, and additionally the sub area of a targeted framing (like shooting 2:1 and framing 1:1.85). The latter is less important, as one would often decide to alter the originally marked sub framing by a Pan & Scan approach in post, so the measured data must not be whats in the final film. But measuring all what gets stored (and NOT the overscan) makes just sense to me. I can have a superbright white sun just around the corner, visible in the overscan, which would lit the amples if it enters the actually to-be-stored area.

Ian's idea of using a circle open/closed for RGB or RAW peaking sounds interesting, but may be not intuitive enough for my taste. I would still have to think about "which is which". Why not have TWO amples side by side, one having in small font "RAW" vertically beside it, the other "RGB".

Then again, Ian's idea could come into play by showing a color DOT when peaking the to-be-saved area, and an opened circle (like brackets?) when peaking inside the selected sub frameing guide (like 1.85 guide when shooting 2:1 or 16:9). Maybe the open circle is still not ituitive enough then, maybe we find something better. The question is anyway if the processing power of the RED ONE would allow to process these things "side by side" at all. But as it all derives from two histograms (the to-be-saved area one, and the centred smaller sub frameing format one), it might be possible.

After all, if the power of the RED ONE processing doesn't allow for both, at least the RAW and RGB ample of the to-be-saved area make sense IMHO and can both be derived from a single histogram, which is just fine I think.

Stuart,

one question:

At which bit depth is the histogram being calculated?
I don't think what we see can be the full 12 bit precision histogram.
I ask because if we knew its only an 8 bit histogram (so 256 steps wide in display without scaling) we could play in photoshop for how we find it to look cool and quickly to understand if something is going to be changed here.
I suspect its a pure 12 bit histogram and we just see a scaled version?

Regards,
Axel


Cheers,
Axel
 
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