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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 :)

Opinion POLL: EPIC native ISO = 800 or ISO = 320?

Opinion POLL: EPIC native ISO = 800 or ISO = 320?

  • Total voters
    159
I think this needs to be cleared up, RAW view (a legacy name from the R1) is probably responsible for most of the confusion in this thread.

1. RAW View is not truly RAW! It's a Gamma/Color space application that is flatter, less saturated and nominally ISO 320
2. RAW View is there for you to quickly see what detail you have in your highlights, not to use as an exposure reference for any mid tones or shadows.
3. RAW View does NOT show actual sensor data, that is linear and B&W and unusable.

By setting the Epic to ISO 800 you are essentially applying a viewing LUT (Meta data) to the image that gives you the best balance of highlight exposure and noise floor.
Regardless of the ISO set on the camera (or which camera) if you use the ETTR method you will end up with the best possible exposure.
My only caveat to that is that on pretty much every digital camera skin tones look best exposed down a 1/2 stop or so.
 
Evin Grant said:
I think this needs to be cleared up, RAW view (a legacy name from the R1) is probably responsible for most of the confusion in this thread.

1. RAW View is not truly RAW! It's a Gamma/Color space application that is flatter, less saturated and nominally ISO 320
2. RAW View is there for you to quickly see what detail you have in your highlights, not to use as an exposure reference for any mid tones or shadows.
3. RAW View does NOT show actual sensor data, that is linear and B&W and unusable.

By setting the Epic to ISO 800 you are essentially applying a viewing LUT (Meta data) to the image that gives you the best balance of highlight exposure and noise floor.
Regardless of the ISO set on the camera (or which camera) if you use the ETTR method you will end up with the best possible exposure.
My only caveat to that is that on pretty much every digital camera skin tones look best exposed down a 1/2 stop or so.
Click to expand...

I agree, as usual, with Evin.

So perhaps RED should rename the RAW mode to "Highlight View" mode.

It would be nice to have this and a "Shadow View" mode. This would clarify things and make
it easy for people to toggle between highlight analysis and shadow analysis modes.
 
Of all the remaining differences between film and digital I see overexposed skin tones as the most critical frontier. Evin likes the skin tones a little under and (not to speak for him too much) I suspect its because when they go even a little bit over on digital they begin to lose character and even shift hue far too easily. Film would typically maintain hue and tone on skin quite well as you ran up the exposure curve. In my way of thinking, its these kinds of issues that make a fuller understanding of the digital process even more important. If you take the "place and fall" approach to setting exposure in a scene where the human in the shot is the critical element, then I might expose for the skin tone and not worry whether I was biasing the exposure to the left or right.

Cheers - #19
 
Blair S. Paulsen said:
The "native" ISO debate seems to be part technical, part philosophical and almost religious. (When someone claimed to be in the 800 club I LMFAO)

Should RED have structured their nomenclature and technical notes to suit the existing framework of a particular group of shooters? Video guys think in IRE, film guys want shutter angles not fractions of a second, histograms are for stills guys, etc. IMO this thread has morphed into a microcosm of the Alexa vs Epic culture wars. In Adrian's world (I've done plenty of DIT days on national TVCs in the LA market myself) the Alexa is very popular and lauded for its fealty to film style conventions right down to the color matrix.

ARRI was determined to make a digital camera for the people who hated digital so they made choices in the Alexa's design intended to make the experience as film like as possible. They chose technically inaccurate, but familiar, terminology and feedback indicators. The result has been generally good exposure choices by most DPs (and their trusty DITs) that have led to consistently successful outcomes. It's the "if it ain't broke don't fix it" approach and in the short term, as many have noted, it has served the Alexa well.

That said, I vastly prefer the RED approach because its based on the actual dynamics and operational characteristics of a digital system. The pain is having to make some effort to learn something new, maybe expand your understanding of imaging metrics, do a couple tests, etc. The gain is that you can become more capable of getting the most out of digital imaging systems in a wide range of scenarios if you understand the interrelationships well enough to better predict the impact of your choices.

When Evin chooses his exposure he has specific targets in terms of code values that will allow him to create the look he wants in post. When I am considering my exposure choice, what I want from the camera system is as much usable feedback as I can get. In terms of ISO setting for the monitoring path I find using 800 consistently offers a valuable reference point and allows me to expose to the right without fear of clipping. By toggling to the RAW view I am quickly able to get a sense of any areas of the sensor that I might be "starving", then either help them or write them off depending on creative intent.

At the risk of feeding those who contend that defining "proper" exposure on the RED cams should be more cut and dried I do have a note that serves me well, YMMV. One of my favorite methods for getting the most usable code values into the RAW data set is to adjust the iris while watching the 800ISO RGB histogram. What I'm looking for is how the values stack up or spread out, particularly when I take it too far to either extreme - how does it behave? Early on I learned the hard way that there were times that exposing to the right as dogma made noiseless but flat images that lacked guts no matter how much I jacked them around in post. Bottom line, each scene and lighting condition has a natural distribution of values and in most cases maintaining an accurate representation of those relationships will yield the most useful starting point for grading.

Cheers - #19
Click to expand...


Good advice.

Concerning your method for getting the best out of a scene's exposure: I usually agree. However, this is in complete opposition to a DP that is attempting to light their scene for a specific exposure (IE: 800 ISO).
 
Evin Grant said:
I think this needs to be cleared up, RAW view (a legacy name from the R1) is probably responsible for most of the confusion in this thread.

1. RAW View is not truly RAW! It's a Gamma/Color space application that is flatter, less saturated and nominally ISO 320
2. RAW View is there for you to quickly see what detail you have in your highlights, not to use as an exposure reference for any mid tones or shadows.
3. RAW View does NOT show actual sensor data, that is linear and B&W and unusable.

By setting the Epic to ISO 800 you are essentially applying a viewing LUT (Meta data) to the image that gives you the best balance of highlight exposure and noise floor.
Regardless of the ISO set on the camera (or which camera) if you use the ETTR method you will end up with the best possible exposure.
My only caveat to that is that on pretty much every digital camera skin tones look best exposed down a 1/2 stop or so.
Click to expand...

Well said....
The name of the raw view I believe is confusing some.
As graeme said the ISO (which is a standard) is manufacturers suggestion for raw..reds suggestion is ISO 800...so according to standard... that's what it is, and a good starting point for most users
 
Martin Stevens said:
I agree, as usual, with Evin.

So perhaps RED should rename the RAW mode to "Highlight View" mode.

It would be nice to have this and a "Shadow View" mode. This would clarify things and make
it easy for people to toggle between highlight analysis and shadow analysis modes.
Click to expand...


From the EPIC's User Manual:


"RAW displays the image without any ISO correction. When selected, the icon “R√” will be displayed in
the Lower Status Group."

This suggests that the EPIC is "natively" 320 ISO.
 
Blair S. Paulsen said:
Of all the remaining differences between film and digital I see overexposed skin tones as the most critical frontier. Evin likes the skin tones a little under and (not to speak for him too much) I suspect its because when they go even a little bit over on digital they begin to lose character and even shift hue far too easily. Film would typically maintain hue and tone on skin quite well as you ran up the exposure curve. In my way of thinking, its these kinds of issues that make a fuller understanding of the digital process even more important. If you take the "place and fall" approach to setting exposure in a scene where the human in the shot is the critical element, then I might expose for the skin tone and not worry whether I was biasing the exposure to the left or right.

Cheers - #19
Click to expand...

I think that this "skin tone" issue will not be a problem once digital camera have the same amount of Highlight Latitude as film.

But, hey, I could be wrong... color science gets better every day with Graeme around.
 
Adrian Jebef said:
From the EPIC's User Manual:


"RAW displays the image without any ISO correction. When selected, the icon “R√” will be displayed in
the Lower Status Group."

This suggests that the EPIC is "natively" 320 ISO.
Click to expand...

Perhaps, just perhaps, the Red Epic Manual needs a little updating in this area.
 
Adrian Jebef said:
From the EPIC's User Manual:


"RAW displays the image without any ISO correction. When selected, the icon “R√” will be displayed in
the Lower Status Group."

This suggests that the EPIC is "natively" 320 ISO.
Click to expand...


And back around the circle we go... *sigh*
 
So is the crux of this just defining what "native" means in this context? Unless semantics is your favorite subject what are we accomplishing here?

For starters signal to noise ratio is actually a far more indicative metric for best exposing a digital sensor than an arbitrary ISO value. Graeme and the Red Team have decided to make ISO 800 the default for the monitoring path and in terms of on set functionality it works well. Based on over 100 RED cam shoots I've been on, setting the ISO to 320 or always viewing RAW can easily lead to overexposing and friction between the camera department and director/producer/client. Show them something that best represents what a WYSIWYG camera output would look like and leave the technical details to the DP/DIT/Colorist.

What may be getting lost, though both Evin and Graeme noted it, is that the RAW check is actually a gamma encoded representation of the true RAW linear light image that would be far too dark to be of any use. While Adrian's quote from the User manual might suggest 320 is the native ISO, I still think this is a trip down the rabbit hole. There's no "magic native ISO number" that will guarantee ideal exposure in every scene.

Cheers - #19
 
OK - there is NO native ISO, only the correct exposure for any scene which will entail the correct ISO setting to put mid grey in the middle of the developed image. We (as in RED) recommend on MX and Epic a starting point of ISO800 for your use. That doesn't mean it's the right ISO for any shot, but one we've found works in a wide variety of circumstances.

To me native ISO only makes sense as a statement in a camera with destructive analogue or digital gain. We don't do destructive gain, so no concept of native ISO makes sense.

Graeme
 
when you say destructive, do you mean where the signal is recorded after gain applied?
 
Perhaps it would help to think of Red RAW as having a dozen film stocks built into it, all with various ASA/ISO ratings.

And then perhaps it would help to think of RedCine-X Pro as having your very own Technicolor or Deluxe Lab right
inside your computer.

So just as Technicolor can push and pull your film negative, so can RedCine-X Pro.
 
thats not a bad way of putting it....
some of the stocks are more noisy then others
 
Yes, some cameras will, even in RAW, bake in digital gain as well as analogue gain (which you expect to get baked in). As Blair notes it doesn't stop the signal being linear, but it does diminish the highlight ability (or if negative gain is baked in) data precision.

Graeme
 
Adrian Jebef said:
Ah, ha! I'd put forth that a "correct exposure" is being able to light your scene in such a way that all of the important details (read highlight and shadow) are CAPTURED by the sensor of your camera and not clipped. The only way in which we will know what RANGE we can light a scene to is to KNOW what range our camera is capable of handling. This range has a midpoint (a place where there is an equal distribution of exposure range above and below 18% Grey). This midpoint is commonly referred to as a sensor's "native sensor sensitivity" and more commonly called it's "native ISO or ASA".
Click to expand...

Graeme Nattress said:
ISO for RAW (and only RAW) cameras is a recommendation.

RAW view has a gain and curve applied to show you what's going on in the highlights. ALL development ISOs have neutral gain because we don't change the analogue gain on ISO. It's all in the digital development curve.


ISO800 gives you 4.5 stops above mid grey, ISO320 therefore gives 3.2 stops above mid grey.

Correct exposure is determined by the scene.

Mid grey in the scene for any given ISO is always mapped to the same point in the image post development curve.

Graeme
Click to expand...

Gunleik Groven said:
Ketch
That was not an attack on you.
I didn't imply that you do not know your camera, just that there is no other right way than the one that gives youthe imageyou are aiming for...


I love how the epic blows out and can sometimes use the noise artistically.
So, technically i am happy to under- and overexpose from a purely technical POV, if that gives me the reslt I want.

Thing is to be in controll. Not discussing rights and wrongs as absolutes.

From a purely technical POV, there are things to be said as to how yo can get a fat, lownoise image.
And i feel pretty comfortable. In being able to do that.

But from an aesthethical POV, that is. Often NOT the image I want.
Hahahaha

So i very often deliberately break the technical premises, to get what I want.

And I feel I did my exposure"right" when I am happy with the result.

THAT was my point.

Not to. Attack you.
Click to expand...


Cool buddy, I miss read it, and I guess at times I read too fast and write too fast, but Graeme has put it in to terminology and numbers and this is what I meant, as of the importance to try and stay at the proper ISO which in my Opinion is the camera's Native, and then expose properly from there.


And yes Adrian, absolutely correct, and this is exactly what I mean to say, and the reason to stay at 800 ISO and expose form there accordingly, making use of more or less lights, and or making use of ND's.
 
Im in the 320 camp. When i first got my first Epic, i was rating at 800 and i always had noise in my blacks- It could have been resolved by more lighting. I dont want noise in my blacks and it doesnt kill me if my highlights clip, because there is no ugly noise. I also always look at the raw image on the touchscreen. My method is not scientific. I always try to have no purple in exposure mode or red for that matter, however if i had to choose between purple or red, I will always go with red (highlights being clipped) because I usually dont need detail in my whites unless its a fashion shoot and the white fabric has detail. But I totally understand the argument for 800 as means for a disciplined approach. And i guess 320 for me is a disciplined approach for preventing noise in the blacks. I cant recall a time when i have shot an exterior without some ND. Again, for me, it's an approach that suits my look, which certainly is not for everybody.
 
At the risk of confusing the issue further, Brook made some points in the older thread about how all digital cameras are doing some things "under the hood" before it becomes an image, or even a set of code values. As users, its of limited to use to even consider how the front end electronics turn native sensor voltages into the values recorded. That said, I do think it could aid understanding to note that every electro-optical system/signal chain maps values along the way. The ISO setting in the monitor path can influence exposure settings indirectly, but in a system that doesn't add global gain (digital or analog) it has no actual impact.

FWIW I think a lot of people are working in situations where the processing of the RAW data set revolves around the camera metadata settings. In that scenario, ISO choices have a downstream impact via standard practice rather than because the code values in the RAW files are actually any different. This speaks to mindset and workflows rather than genuine exposure considerations.

In my perfect world I'm always "shooting for the darkroom" by capturing a data set that facilitates creating the desired image during the processing phase (digital darkroom) to make the RGB picture I have in mind.

Cheers - #19
 
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