Exposure 101...

[Jannard]

This topic has been covered before. Many of you know all this stuff. But there are new RED shooters everyday and some that are still struggling with exposure. Buried in this post is a question for the community. We'd love your opinion.

There is plenty of DR in a RED ONE to make great images... many have proven that. But the range is limited enough that you can easily miss the window if you are not careful. Let's recap a very simplistic starting point for exposure to keep you out of trouble.

Under-exposure leads to noise. Over-exposure leads to clipped highlights. So... don't do either, unless you really want to.

1. Make sure your monitor/LCD's brightness is set correctly. The RED LCD's need 4 or 5 clicks down from full bright in most circumstances. If set too bright... it seduces you to stop down and under-expose.

2. ETTR. Expose to the right. Just under the point of clipping. That keeps you away from noise in the shadows and keeps detail in the highlights. In a dark scene you may choose to allow some specular highlights clip. See False Color or Zebras below.

Use your tools.

Quickly set approximate exposure by looking at the LCD.

Check the color bar next to the histogram (which corresponds to False Color colors and originates from RAW). Turn out the top red box. That is the equivalent to clipped. Don't worry about the orange, yellow or other colors... they are probably supposed to be lit.

The Stop Lights next to the color bar are from the RGB path! Don't let them fool you. Sometimes they are on and you still have detail in the highlights. We are likely to change this in a future build to represent RAW and not the RGB path. Thoughts?

Use False Color. Red means clipped and purple means super dead. I set my top left LCD button to False Color in User Prefs. If it (something in the scene) is red... it is dead (clipped). There are time when you might be OK with that, but False Color tells you exactly what is clipped. You choose instead of guess.

Use Zebras. They will tell you exactly which highlights are blowing (you need to know)... you can also set them for the shadows, they "buzz alert" when you are likely to encounter a lot of noise. You can set the top and bottom limits to each of them.

If anyone cares to add... please do.

Jim

 

[Stephen Pruitt]

Very helpful, Jim. . .

I, personally, would like to hear more about using the zebras for shadow exposure and the "buzz alerts" you mentioned.

Stephen

 

[Tim Whitcomb]

This is an awesome frame of reference. We just bought a low Ser # RED ONE
(our first) and look forward to testing these parameters.

I like how Michael Cioni put it at REDUSER Party. "Shoot a thick negative or Thick Histogram"

The less you clip or produce noise, and the more accurately you expose, the more latitude in post when correcting or color grading.

Thanks for sharing

 

[Shawn Nelson]

Jim, great post, this needs to be in video form on Red.com, prominently visible, a lot of people suprisingly don't come here, especially the people that need this info.

 

[Charles Angus]

I posted this a while ago, but this seems like a good place to get more response.

I've been thinking more about ETTR, exposure practices in general, and keeping noise levels consistent.

With film, consistent noise levels are easy to maintain, as they are locked in by the film stock / processing technique, so long as you are consistent with your exposure.

With digital, exposed by the ETTR method, I am finding that the the change in noise level from shot to shot can be objectionable. A good example of this was Slumdog Millionaire - noise levels were very inconsistent, even from one shot to the next within a scene. I found it very distracting.

I was wondering how other people felt about ETTR and consistent noise levels. Are people concerned about this at all? Are people using a "scene-ETTR" approach, picking an exposure that should work approximately for the whole scene while keeping information in the shoulder as much as possible? Are people lighting film-style and not using ETTR at all?

I personally think I will go back to exposing more film-style for digital, trying to keep a consistent light level and exposure for a whole scene, rather than using ETTR for each shot. More of a "scene-ETTR" approach.

 

[Jannard]

In a well controlled exposure... there is very little noise.

Jim

 

[Kim Frank]

Jennard,
Thank you for repeating all this for guys like me...
I'm always using Histograms and Exposing to the right.
But I thought False Colour wouldn't read properly in RAW mode?
I thought I read that over here, or has that been fixed?
Im wondering about the different ISO/ASA settings.
Do they really effect the sensor or just the Metadata and what is monitored.
And Im wondering about the RGB Channels...
Do I have to balance them equaly in lighting Situations lower or higher than 5000K?
Im sorry for my written english and stupid questions,
but I love to work with RED and would love to find out!
REGARDS
KIM

 

[Frank Weeks]

I like how Michael Cioni put it at REDUSER Party. "Shoot a thick negative or Thick Histogram"

Yes. one of the most helpful tips from the gathering.

Jim, great post, this needs to be in video form on Red.com, prominently visible

agreed

 

[Nick Gardner]

I was just thinking the other day about when the Varicam came out, and everyone was trying to figure out what to do with it in film gamma mode. What I did with the Varicam is still pretty much what i do with the Red 90% of the time and the results are very good.

Pick some thing in the frame as your white reference. The thing that is going to be correctly exposed white. Could be a guys ball cap, a t shirt, the slate, a flyer on a telephone pole- whatever. On Varicam I would let my 70IRE zebra's hit my reference white. That then protects your highlights and keeps your exposures very consistent from scene to scene, so you don't make the colorist loose his mind.

This is a great way to be in the ballpark quickly and easily even in run and gun situations.

Nick

 

[Jannard]

Very helpful, Jim. . .

I, personally, would like to hear more about using the zebras for shadow exposure and the "buzz alerts" you mentioned.

Stephen

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

On camera menu- Video/Viewfinder/Zebras

Configure 1. Set this for the highlights. Low IRE and High IRE are the threshold and limit of the zebra range.
Configure 2. Set for shadows. Again set High and Low IRE limits.

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

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

 

[Raul Gonzo]

Jim, do think exposing will be harder to miss with Monstro?
I understand there will always be a way to under/over expose.
But with the possibility of 13+ stops of DR, would that give people a little more elbow room?

 

[Jeff Kilgroe]

The Stop Lights next to the color bar are from the RGB path! Don't let them fool you. Sometimes they are on and you still have detail in the highlights. We are likely to change this in a future build to represent RAW and not the RGB path. Thoughts?

Yes! If the stop lights can be made to represent RAW color channels and not RGB derivatives, that would be excellent. The camera records RAW, so all meters should be representative of these RAW values wherever applicable and/or possible.

Other than that, excellent summary for exposure and those new to this. I want to further emphasize the ETTR methodology! Exposing to the right, just short of clipping is the best way to avoid noise in your shots.

Blue channel exposure is also something that should be of concern to those shooting under tungsten or other non-daylight-balanced sources. As with most CMOS type sensors, the RED One is less sensitive to blue light. Sometimes, to avoid high noise levels under tungsten light without filtration or gels for correction, extra light may be needed. The camera often sees tungsten light differently than many commonly used light meters. For those who shoot regularly under tungsten light, 1/4 and 1/2 CTB filters are a great addition to the kit.

 

[Michele Gavazzeni]

this needs to be in video form on Red.com, prominently visible

Yeah an image speaks for a 1000 words!

 

[Kyle Mallory]

RGB lights exposed for RAW, PLEASE. Perhaps configurable? Or maybe that will just confuse people more.

I remember reading about the shadow zebra's a long time ago, nearly a year or more ago. I think it was in the RED manual or something. It has been very handy in a few situations, but generally, if you ETTR, and compose your scene well, any noise will be buried under the the rest of a beautifully exposed frame.

 

[Kim Frank]

(don't know yet how to quote several times out of the same post... everything bold has been written by Jeff Kilgroe... )

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

That would be awesome!!!

Exposing to the right, just short of clipping is the best way to avoid noise in your shots.

Because youre staying ahead of the noisefloor, right?

For those who shoot regularly under tungsten light, 1/4 and 1/2 CTB filters are a great addition to the kit.

But what to do under mixed lighting Situations?
Tungsten Inside, Daylight outside...
Or what to do when shooting Rock/pop Concerts...

 

[David Mullen ASC]

Camera filters can't correct a mixed light situation -- the color temp differences remain even if you shift the overall image one direction or the other. If you want to correct the mismatch, you have to decide what sources you are going to match other sources to, by using lighting gels, changing bulbs, etc.

Now sometimes you find a location with very little daylight and a lot of tungsten (like a room with a small window) where the simplest thing will be to correct the window to tungsten by gelling it orange. But once everything becomes tungsten-balanced, then you'll get better results on the RED using blue camera filters to raise the overall color temp.

 

[Antoine Fabi]

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

 

[Andrew Walker]

This is an awesome frame of reference. We just bought a low Ser # RED ONE
(our first) and look forward to testing these parameters.

I like how Michael Cioni put it at REDUSER Party. "Shoot a thick negative or Thick Histogram"

The less you clip or produce noise, and the more accurately you expose, the more latitude in post when correcting or color grading.

Thanks for sharing

I have to agree with you on the Placer City presentation. It was nice to have someone tell you to shoot a thick negative because most of the film guys that got a Red understand that. Also it makes a lot of sense to shoot that way since you get the most out of your DR...or at least that's what I have found.

Of course you have to use good judgement with this as well because it isn't the end all be all. False color is one of the best tools in the Red for setting exposure.

 

[Mark Warren]

Although some of the in camera indicators are useful, (focus assist particularly) when all is said and done (for me)... when I use my hand-held light meter, I've had no problems whatsoever, not a one with exposure.

 

[Casey Green]

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

On camera menu- Video/Viewfinder/Zebras

Configure 1. Set this for the highlights. Low IRE and High IRE are the threshold and limit of the zebra range.
Configure 2. Set for shadows. Again set High and Low IRE limits.

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

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

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.