Exposure 101...

[Stuart English]

Shadow Zebra

Shadow Zebra

Stuart just showed me this trick... pretty slick.

I can't remember offhand what we figured out what numbers worked the best so I need to check and see if Stuart remembers.

I'd recommend that you set up Zebra for shadows to match the False Color Exposure Meter overlay.

Which would be LO = 0 IRE and HI = 5 IRE which is Dark Blue and Medium Blue.

Or set to the next higher pair of colors which would be LO = 2 IRE and HI = 8 IRE

 

[Stephen Pruitt]

I, personally, have found that the seven color light meter is pretty much worthless. If I used that red light on top to gauge exposure, I'd have nothing but underexposed footage every time. Just now, I took the camera into my basement and turned off all the lights. I then turned on ONE tiny light across the room and, as soon as I panned the camera so that that light entered the frame, BANG, the red light lit up. The overall exposure was almost totally black, but that red light was lit up.

Given this is true, how could I ever possibly use that red light as an exposure gauge?

Stephen

 

[Stuart English]

Exposure

Exposure

I, personally, have found that the seven color light meter is pretty much worthless. If I used that red light on top to gauge exposure, I'd have nothing but underexposed footage every time. Just now, I took the camera into my basement and turned off all the lights. I then turned on ONE tiny light across the room and, as soon as I panned the camera so that that light entered the frame, BANG, the red light lit up. The overall exposure was almost totally black, but that red light was lit up.

Given this is true, how could I ever possibly use that red light as an exposure gauge?

What its telling you is that you have at least 2% of the pixels in RGB space at maximum value. And in an scene as you describe, you have a choice to make. Do you want it to clip, and continue to raise the level of the blacks, or is that point of information what is most important to you.

Next question I would have is what setting is the ISO at and what do the other meters - such as Histogram and RAW meter - tell you?

 

[Matt Gottshalk]

Thanks for this post, Jim.

I would like to see the Stop Lights represent RAW.

I love the False Color mode, and think it is one of the best tools available on the RED, HOWEVER, it would be great to add a False Color 2 mode which only had the color represent these 4 modes:

PINK = Clipped Hilights
RED = Almost clipped

Grey Scale = all shades in between

Dark Blue = Almost Under Exposed
Dark Purple = Under Exposed

Some of the other colors in the False Color mode are hard to remember and also make viewing the image confusing.

I would love a False Color 2 mode as an option.

thanks for listening to user feedback.

That sounds like a VERY useful option.

 

[Scott Webster]

The camera records RAW, so all meters should be representative of these RAW values wherever applicable and/or possible.

Please baby jebus grant us this.

I would like to see the Stop Lights represent RAW.

I love the False Color mode, and think it is one of the best tools available on the RED, HOWEVER, it would be great to add a False Color 2 mode which only had the color represent these 4 modes:

PINK = Clipped Hilights
RED = Almost clipped

Grey Scale = all shades in between

Dark Blue = Almost Under Exposed
Dark Purple = Under Exposed

Some of the other colors in the False Color mode are hard to remember and also make viewing the image confusing.

I would love a False Color 2 mode as an option.

Casey, great, great idea.

 

[Jeff Kilgroe]

I like Casey's suggestion too. Would also like to keep the green or some sort of indicator for 18% grey or have an option to toggle it in such a mode. Possible?

 

[Tim Sutherland]

It would be nice to also have a 'raw view' that changes with color temperature settings (would be equivalent to setting Camera RGB - Rec709 in Red Alert) so you can see what your actual IRE values in the RAW are under tungsten.

Given that and stop lights/false color always reading off the raw, then it would be much easier to see what you've got. I think zebras, however, could monitor the RGB path.

While we're on the subject, can we get REC709 tweaked so that it matches the camera BARS that get sent out? I ask because when you set a monitor to the Bars in the test pattern, then pull up REC709, the colors look a little tweaked. If I remember right, they seem a bit golden and over saturated. Any chance on this? That would also make a waveform and vectorscope more accurate for those who come from a pro video background and really want to use those tools. (I understand this goes against the idea of RAW quite a bit, but having a more accurate 709 output would be a huge help).

Tim

 

[Steve Sherrick]

Jim, great post as this is the type of stuff I love to see on this forum.

I too would love to have the meters represent RAW. The RAW meter is effective and I do monitor it, but I'd love to have other meters tuned to the RAW signal as well. I'm hoping that False Color will be tuned for RAW in upcoming firmware, although as Stuart has mentioned it's pretty close even now. The stoplights could be useful for quick glance to see if you're clipping a channel in the RAW while still monitoring your REC709 or Redspace. I do use the zebras for highlights, but I need to start using the low end as well.

When you nail exposure, the results are amazing. The thick negative is such a key. Best test for someone new to RED is shoot something, exposing what you think is a good exposure. Then do some bracketing. Bring it into RED Apps and start playing. Try playing with filters such as CTB/80 series for tungsten. Try techniques such as Macgregor's SC profile. Learn what makes RED sing. After that, no more worries. Shoot as much as possible, process as much as possible.

I'm having fun grading some stuff tonight. Amazed at how some low light stuff held up.

 

[Jannard]

Lots to chew on... we are listening.

Jim

 

[AIO Films]

When you are clipping... you see what is clipping. When you under-expose, the shadows getting hit with potential noise start dancing up a storm. Easy to see.
Jim

I have a silly question. What is underexposure? According to these physical characteristics, all the dark area in a scene (which supposed to be dark in the story) will be noisy? Or we have to refrain from having any dark area in the shot all together in order to avoid noise?

My question might sound cynical, but I am not. I am genuinely puzzled by it. Please help.

 

[Shawn Nelson]

Lots to chew on... we are listening.

Jim

Whether video or not, there needs to be something on the main red.com and net merely here. Have you considered a Red University or Reducation section of the Red.com site?

 

[Joel Kaye]

Use False Color.

I'd use False Color more if I could put it on a button while edge focus assist is on another button. I'd hope that is on the short list for things to do.

@Stuart: What's the Zebra setting to show a true highlight clip? Does that vary with ISO changes? THX!

@Stephen. Since we know that any hot highlight is going to cause a stoplight to light up so I usually reframe out obvious hotspots that I'm planning on letting blow out when checking exposure.

 

[Steve Sherrick]

I have a silly question. What is underexposure? According to these physical characteristics, all the dark area in a scene (which supposed to be dark in the story) will be noisy? Or we have to refrain from having any dark area in the shot all together in order to avoid noise?

My question might sound cynical, but I am not. I am genuinely puzzled by it. Please help.

Often times, if something is meant to be dark, with little need for detail you can toss that info away, i.e. crush it which will eliminate the noise for the most part. However, the RED can see into the shadows, sometimes going into territory where noise will be present and you have some decisions to make.

 

[David Mullen ASC]

I have a silly question. What is underexposure? According to these physical characteristics, all the dark area in a scene (which supposed to be dark in the story) will be noisy? Or we have to refrain from having any dark area in the shot all together in order to avoid noise?

My question might sound cynical, but I am not. I am genuinely puzzled by it. Please help.

No, just because an area is dark doesn't mean it has to be noisy. Obviously an image will normally contain tones below 18% grey value -- it would look pretty boring if it didn't!

Basically at the extreme bottom end of exposure, there is information being captured... but it lies in the noise floor, so if you can live without seeing that faint detail in the murk, you are better off letting it go to black in the final color-correction and thus hiding the noise there.

As for noise in general shadow areas above black, it all depends on the overall level and your color-correcting decisions -- if you have enough exposure in the shadows to push them "down" a little in brightness, then they will look fairly clean, but if you don't have enough exposure and have to lift them "up" at all, then noise will also appear. So you can light for mood all you want as long as you don't change your mind and attempt to bright up low-level detail in the final color-correction, and if you want even cleaner, less noisy shadows, add some weak fill to them and basically crush the bottom end down a little to darken it.

 

[Adrian Correia]

I'd use False Color more if I could put it on a button while edge focus assist is on another button. I'd hope that is on the short list for things to do.

@Stuart: What's the Zebra setting to show a true highlight clip? Does that vary with ISO changes? THX!

@Stephen. Since we know that any hot highlight is going to cause a stoplight to light up so I usually reframe out obvious hotspots that I'm planning on letting blow out when checking exposure.

yes....please incorporate this!! My ACs are always fighting me on this....

also the pink, red, grey to blue, purple false color 2 sounds great!

 

[Steve Freebairn]

I think the most helpful thing RED could do is make it possible for false color, the stoplights, and the histograms to be based on raw when viewing in redspace or rec709

 

[Roberto Lequeux]

This is likely only due to my limited hands on experience with Red One, but how do you read highlight clipping on the traffic lights? It seemed that as I began to overexpose the top end got rolled off gently as opposed to simply getting cut off at the end of the chart. Is there a setting that doesn't roll off the highlights? RAW mode perhaps? I am not even sure what mode I was viewing with.

 

[Jarred Land]

Whether video or not, there needs to be something on the main red.com and net merely here. Have you considered a Red University or Reducation section of the Red.com site?

Yes.... Reducation is being integrated onto the next Red.com as we speak

Education is something we have been really bad at, and luckily Ted has devoted the next chunk of his life to fixing

 

[Mark Phelan]

Thanks for this post, Jim.

I would like to see the Stop Lights represent RAW.

I love the False Color mode, and think it is one of the best tools available on the RED, HOWEVER, it would be great to add a False Color 2 mode which only had the color represent these 4 modes:

PINK = Clipped Hilights
RED = Almost clipped

Grey Scale = all shades in between

Dark Blue = Almost Under Exposed
Dark Purple = Under Exposed

Some of the other colors in the False Color mode are hard to remember and also make viewing the image confusing.

I would love a False Color 2 mode as an option.

thanks for listening to user feedback.

The False Color is sort of a cruel joke for those of us who are partially colorblind. I tend not to use it because it would be hard to discern the colors like dark blue and dark purple, from one another. Wish there was some other combination that would be more apparent. For now, I'll stick with the histogram/stop lights. Oh, and thanks for giving us the option to use different methods.

 

[Patrick Tresch]

Ban REC709!

Ban REC709!

Hi Jim,

Here is a very simple trick that worked so well for me.

I use REDSPACE (no other gamma adjustment, i like the factory REDSPACE curve as is) for monitoring in EVF and LCD.
BUT, considering the camera is 320 ISO native, most of the time, i set ISO to 250 because REDSPACE boosts the midtones, so it is now back very close to RED709 ISO 320 midtones levels.

And the great thing is that the whites clip at almost the same level as RAW.
It's great.

Maybe this trick is naive, but it is simple, reliable (for me), never screwed a shot with this setting.

Antoine

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