Scarlet - Native ISO

[Ryan De Franco]

Gunleik's tests revealed that the MX sensor clips highlights faster when rated lower (say, at 320 instead of 800), and the noise floor increases when you rate above 800. The sensor's actual ISO be damned, 800 is the spot for maximum dynamic range.

That being said, I've found myself rating clips shot at 800 at 640 or 500 in RedCine recently, for the right scene only ISO seems to deliver the "dim" tonality I'm looking for, not gain gamma or lift... that being said, I have no idea what I'm doing as a colorist

 

[Noah Yuan-Vogel]

Gunleik's tests revealed that the MX sensor clips highlights faster when rated lower (say, at 320 instead of 800), and the noise floor increases when you rate above 800. The sensor's actual ISO be damned, 800 is the spot for maximum dynamic range.

well yeah, but the latitude is still the same. Of course low iso clips sooner relative to grey point, raw white clip is the same for all modes, and raw noise floor is the same as well, but generally Redcolor2 and Redlogfilm are designed to simply move mid point and redistribute shadow/highlight latitude accordingly. Don't forget that higher isos also clip later and lower isos also have lower noise.

Personally I'd consider shooting at a higher iso since I love extra highlight latitude and dont care as much about shadow latitude and I'm not afraid of a little noise

 

[Ryan De Franco]

good point noah, should've said maximum dynamic range in both under- and over exposure.

 

[Stephen Wheeler]

Thank you everyone. This has been one of the best and most informative threads I've encountered on this site. I hope Simon got the info he was looking for.

 

[Graeme Nattress]

Just to be clear - Dynamic Range is constant. It doesn't matter what ISO you shoot, the total DR available is the same. This would not be the case in an analogue gain situation where typically a stop of DR is lost for every stop up in ISO you go.

What does change is highlight (and because DR is constant, consequently shadow) latitude. For each stop in ISO you go up, you gain a stop of highlight latitude and loose a stop in the shadows. Another way of thinking of "loosing" the stop in the shadows is that the shadows will get more noise in them.

Similarly if you go down a stop in ISO, you loose highlight lattitude and gain it in the shadows. This is fine until the point where you loose too much in the highlights and start to get clipping. That is why we only recommend you go below ISO320 if you're very careful and watch those highlights!

Graeme

 

[Martin Stevens]

Just to be clear - Dynamic Range is constant. It doesn't matter what ISO you shoot, the total DR available is the same. This would not be the case in an analogue gain situation where typically a stop of DR is lost for every stop up in ISO you go.

What does change is highlight (and because DR is constant, consequently shadow) latitude. For each stop in ISO you go up, you gain a stop of highlight latitude and loose a stop in the shadows. Another way of thinking of "loosing" the stop in the shadows is that the shadows will get more noise in them.

Similarly if you go down a stop in ISO, you loose highlight lattitude and gain it in the shadows. This is fine until the point where you loose too much in the highlights and start to get clipping. That is why we only recommend you go below ISO320 if you're very careful and watch those highlights!

Graeme

So......does this mean that at ISO 800 there are an equal amount of
stops above and below middle gray? Can you answer this question directly?

 

[Graeme Nattress]

No, at ISO800 there's still more stops below than there are above. I think there's 4.5 above at ISO800, but the stops below are personal noise tolerance defined, so we picked ISO800 as "good safe starting point".

Graeme

 

[Martin Stevens]

No, at ISO800 there's still more stops below than there are above. I think there's 4.5 above at ISO800, but the stops below are personal noise tolerance defined, so we picked ISO800 as "good safe starting point".

Graeme

THANK YOU!

So at what ISO do we need to rate Epic MX so that the amount of highlight latitude
is equal to that of modern 35mm Negative?

I'm not including HDRx in this.

 

[Graeme Nattress]

Martin, I did measure 5219 while working on REDLogFilm, to help me understand how film "works" so to speak - I'd have to go back through my notes and see. I remember the "overall" dynamic range being very similar though between RED One M-X and the 5219.

Graeme

 

[Martin Stevens]

Martin, I did measure 5219 while working on REDLogFilm, to help me understand how film "works" so to speak - I'd have to go back through my notes and see. I remember the "overall" dynamic range being very similar though between RED One M-X and the 5219.

Graeme

In my mind 35mm Neg always seems to have its ISO set so that say out of the 14 stops of DR that it has the highlight latitude is about 8 stops
and the shadow latitude is about 6 stops.

So to get the MX to match this a very high ISO would be needed, maybe ISO 6400. Am I crazy?

Thank you a million times for HDRx! Love your work!

 

[Graeme Nattress]

Definitely more in the highlight side of things than shadow - which is severely grain-limited. It's also tricky because of the smooth highlight roll-off and how to compare that to the linear nature of a digital sensor which gives increasing information in highlights until it stops, rather than less and less and less and less until it's all gone. They're different beasts...

Graeme

 

[Martin Stevens]

Definitely more in the highlight side of things than shadow - which is severely grain-limited. It's also tricky because of the smooth highlight roll-off and how to compare that to the linear nature of a digital sensor which gives increasing information in highlights until it stops, rather than less and less and less and less until it's all gone. They're different beasts...

Graeme

Yes, very different and difficult to truly compare.

Film fails beautifully in the highlights. Digital can hard clip and be not so pleasant.

But then again, with your Alchemy and your FLUT curves we have beauty again.

Oh, wow....when you unleash the Dragon sensor....whoa!