ISO vs FLUT

[Dennis Guskov]

Seems that the image does not change if I do e.g. ISO 640, FLUT 0 or ISO 320, FLUT +1

Is there any difference? What is it? When would you want to use one over the other?

 

[Graeme Nattress]

FLUT is fine control over ISO, so ISO320 +1 is the same as ISO640. Similarly ISO800 -1 is the same as ISO400. Generally set rendering intent with ISO then fine-tune, if necessary on the FLUT.

Graeme

 

[jake blackstone]

FLUT is fine control over ISO, so ISO320 +1 is the same as ISO640. Similarly ISO800 -1 is the same as ISO400. Generally set rendering intent with ISO then fine-tune, if necessary on the FLUT.

Graeme

So all this endless talk about FLUT working by mostly adjusting mids and preserving highlights is just ...talk?

 

[Graeme Nattress]

No Jake, I don't know where you get that from? ISO and FLUT work on the same "protect highlights" math. If you want "pure gain" that hard clips, you can use "Exposure".

Graeme

 

[Dennis Guskov]

Thanks for clearing that up
promptly too were you waiting for it?

 

[jake blackstone]

No Jake, I don't know where you get that from? ISO and FLUT work on the same "protect highlights" math. If you want "pure gain" that hard clips, you can use "Exposure".

Graeme

Interesting.
Graeme. I'm sure, I'm not the only one, that seen this explanation here
Here is one of MANY posts on the subject, that I found immediately:
"Personally, my workaround is to just convert at 250ISO (which maintains all highlight detail) with a little bit of FLUT to get overall exposure right (which moves exposure but doesn't clip highlights as much"
In other words, he decreases ISO to 250 and then boosts exposure with FLUT back to where it was before, thinking, that this way he's get better highlight exposure...

 

[Graeme Nattress]

Well, if you use REDLogFilm you won't loose highlights at all over a very very wide range of ISO..... Or use the EXR output.....

Graeme

 

[jake blackstone]

Well, if you use REDLogFilm you won't loose highlights at all over a very very wide range of ISO..... Or use the EXR output.....

Graeme

Yes of coarse it is better to use RedLogFilm instead of RedColor2 or upcoming RedColor3 for highlight protection. But what does it have to do with question at hand, that after all this time, since FLUT was introduced, there is still huge number of people, that are confused by what FLUT is?

 

[Dennis Guskov]

"doesn't clip highlights as much"

I heard that too, hence this thread but if the man himself says that's not true, that's enough for me.

 

[Mikael Lubtchansky]

ISO will just jump in 0.33 stop increment vs FLUT can be much more precise to adjust the same value that boost overall brightness but protect hightlight with a smooth curve...

 

[jake blackstone]

I FLUT can be much more precise to adjust the same value that boost overall brightness but protect hightlight with a smooth curve...

Well, there you go Graeme. That is what I'm talking about. Why can't you or Red just come out and clearly state, that FLUT and ISO are exactly same thing, except FLUT has finer ISO control and it has nothing to do with changing the curve? Hasn't it been over a year for FLUT and people are still confused...

 

[Graeme Nattress]

Well, there you go Graeme. That is what I'm talking about. Why can't you or Red just come out and clearly state, that FLUT and ISO are exactly same thing, except FLUT has finer ISO control and it has nothing to do with changing the curve? Hasn't it been over a year for FLUT and people are still confused...

I thought I had on numerous occasions.

Graeme

 

[Matthew Scott]

So FLUT is a curve for ISO, awesome! So now, what is difference between that and using the Luminance/RGB curves?

 

[Graeme Nattress]

Difference is that it's darn easy to use and utterly automatic. Graeme does the work so you don't have to.

Graeme

 

[Mikael Lubtchansky]

So FLUT is a curve for ISO, awesome!

As I understand it, RED ISO adjustments will always use a curved shape to roll off highlights.
FLUT is not a 'curve for ISO' but just a finer way of adjusting the same virtual ISO value to develop the RAW image using more precision that 1/3 of a stop.
A bit like being able to set your ISO value to 753 ISO instead of being forced to use traditional (pre digital ISO values of 400, 500, 640 to 800 etc) but that would be confusing, so they added that FLUT value...

Jim always recommended to let FLUT at 0 in camera and just use it in post to adjust the "exposure"
It exists in cameras metadata just so that you can load a preset with a FLUT value if needed but it can be confusing to adjust it on set as it will "change" your ISO value.

 

[Graeme Nattress]

As I understand it, RED ISO adjustments will always use a curved shape to roll off highlights.
FLUT is not a 'curve for ISO' but just a finer way of adjusting the same virtual ISO value to develop the RAW image using more precision that 1/3 of a stop.
A bit like being able to set your ISO value to 753 ISO instead of being forced to use traditional (pre digital ISO values of 400, 500, 640 to 800 etc) but that would be confusing, so they added that FLUT value...

Jim always recommended to let FLUT at 0 in camera and just use it in post to adjust the "exposure"
It exists in cameras metadata just so that you can load a preset with a FLUT value if needed but it can be confusing to adjust it on set as it will "change" your ISO value.

That's a pretty good explanation and use case for FLUT.

Graeme

 

[jake blackstone]

I thought I had on numerous occasions.

Graeme

Yes you had many, many times and yet, confusion persists
Could you point us to any kind of definitive white paper-like official Red position on what is FLUT, Alchemy, RedFilmLog curve etc.
Saying "just try it, you'll like it" doesn't cut it...

 

[Matthew Scott]

As I understand it, RED ISO adjustments will always use a curved shape to roll off highlights.
FLUT is not a 'curve for ISO' but just a finer way of adjusting the same virtual ISO value to develop the RAW image using more precision that 1/3 of a stop.
A bit like being able to set your ISO value to 753 ISO instead of being forced to use traditional (pre digital ISO values of 400, 500, 640 to 800 etc) but that would be confusing, so they added that FLUT value...

Jim always recommended to let FLUT at 0 in camera and just use it in post to adjust the "exposure"
It exists in cameras metadata just so that you can load a preset with a FLUT value if needed but it can be confusing to adjust it on set as it will "change" your ISO value.

Thanks for the explanation Mikael

 

[Marc Wielage]

Well, there you go Graeme. That is what I'm talking about. Why can't you or Red just come out and clearly state, that FLUT and ISO are exactly same thing, except FLUT has finer ISO control and it has nothing to do with changing the curve? Hasn't it been over a year for FLUT and people are still confused...

I'm still trying to figure out why somebody would use that, vs. just correcting the exposure in final color-correction. I don't get the need to be this precise on the set. Just get a decent exposure and move on, knowing you can fix it later.

 

[jake blackstone]

I'm still trying to figure out why somebody would use that, vs. just correcting the exposure in final color-correction. I don't get the need to be this precise on the set. Just get a decent exposure and move on, knowing you can fix it later.

I too have no idea why someone would need to set ISO to 837