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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 :)

Profile: SC 4.1 250ISO

David, the reason for setting the ISO to 250 and start from there is simple:

Fooling the system. At 320ISO the camera is hidding about 1/3 of stop in the highlights. At 250ISO it´s hidding nothing.

RED hardware and software boosts the signal (+ and -) starting from a setting of aprox. 275ISO. I think i know the reason for this but i wouldn´t like to speculate.

Also at 250ISO the whites don´t go much more than 100IRE. If you´d like to go up to 107-109, you´d have to set something like 275ISO (but you can´t).
Also at 250ISO the lightmeter reading will match the ISO displayed in camera. So as DIT you don´t have to explain to the DP why he needs to set the ISO of his lightmeter to a different value than what the camera has. This is coincidence.

As you comment, with a profile like this dailies go straight from the QTs proxies. ANd in the color grading suit there is no need to tell the colorist to search for hidden info. It´s all there from the beggining. (Note: for heavy Color grading, i recommend reseting the curve and using redlog).
 
Miguel "Macgregor" De Olaso said:
So as DIT you don´t have to explain to the DP why he needs to set the ISO of his lightmeter to a different value than what the camera has.
Click to expand...

what if you only shoot in RAW mode, not using false color, only the histogram?

btw. i like mac`s style of making things work for him.
 
David,

others

or

who-else:

YOUR SHOULD NOT FORGET THE FOLLOWING:

"You're wasting your time trying to help Macgregor. He doesn't want nor he appreciates anybody's advice."

LINK>>>

I'm terribly sorry and know it's not so easy but after all everybody should be aware of it!!!!!!!!!!!!
 
I understand now why Miguel uses the 250 ASA setting in order for that last 1/3-stop of recorded RAW highlight detail to be "pulled down" into view in the Rec 709 monitoring space & for QT dailies. Not sure it's absolutely necessary though but I understand why now.

Let's not get personal when discussing an exposure technique. A difference of 1/3 of a stop is no excuse to attack someone.
 
David Mullen ASC said:
Let's not get personal when discussing an exposure technique. A difference of 1/3 of a stop is no excuse to attack someone.
Click to expand...

Nah. That would be 2/3rds of a stop. We're not there yet. ;)

:sifone:
 
As I wrote in another thread I did some tests with one of the best dop in Italy, he was complaining about the red one and its "fixed" asa and color temperature, saying with film stocks he has more possibilities to shoot in different situations (but he will shoot a feature on red with an international director soon).
So I was thinking (starting from the profile of Macgregor) that it could be interesting developing new profiles for different conditions like: 500 iso tungsten, 250 iso and so on and also profiles similar to some fuji or kodak film stocks. I'm not a dop at all and I don't know if it's possible (in theory making profiles is easy but making working profiles especially for tungsten lights it's another thing) but it could be an idea or could be a nonsense as the red is a raw camera and you can get the look that you want in post. What do you think?
 
David Mullen ASC said:
I understand now why Miguel uses the 250 ASA setting in order for that last 1/3-stop of recorded RAW highlight detail to be "pulled down" into view in the Rec 709 monitoring space & for QT dailies. Not sure it's absolutely necessary though but I understand why now.
.
Click to expand...

Glad I'm not the only one that was confused.
 
Just shot some tests using this profile and then bringing the files into RED Alert to play around with and DOP seems happy with this profile. Looks like we'll be using it on the feature we're shooting. His meter was spot on with the exposure in camera.
 
Sanjin Jukic said:
David,

others

or

who-else:

YOUR SHOULD NOT FORGET THE FOLLOWING:

"You're wasting your time trying to help Macgregor. He doesn't want nor he appreciates anybody's advice."

LINK>>>

I'm terribly sorry and know it's not so easy but after all everybody should be aware of it!!!!!!!!!!!!
Click to expand...

It's a shame 95% of what you post is gibberish, because the other 5% of the time, you post links to some really interesting stuff.

Best,
R.
 
Ruairi Robinson said:
It's a shame 95% of what you post is gibberish, because the other 5% of the time, you post links to some really interesting stuff.

Best,
R.
Click to expand...

Great!!!

Thanks for letting me know your analysis.

Also hope that you are fine.
 
In all this.... I've lost the link to the DOWNLOAD
I'd like to test it!
Someone can put me in the right direction?
 
Thanks Macgregor... this is really cool stuff!.. Your anylisis is very thorough. I had developed an aversion to shooting with the REDspace look... a bit to pushed for my liking. This is the exact kinda "straight" look I thought would be rad, and lo and behold someone did all the thinking for me!

I read through the whole thread, a bit to wrap my head around but I got a bit of grasp for it now... I like to understand a bit of the under the hood stuff....
 
Can someone please check, cos it seems the link is broken
and i would sure like to download SC 4.1 250ISO
 
Hi, the link works for me.

The question now would be: Red Team says that the native ISO of the sensor is 320ISO.

My first question is what do they understand by native ISO in a raw camera.
And the 2nd question would be, do they refer to 320ISO as the setting in camera? Or as the International Standard used by lightmeters? Because they don´t match and one or the other has to be the right one.

In mi opinion the best approach for defining something as native ISO would be that one that sets mid grey in the middle of the system zone / dynamic range of the sensor. In this case a real 320ISO seems good to me (so close to the 250ISO of the SC41). But then the engineers should redesign the output video signal.
If by 320ISO they mean the 320 camera setting then i don´t understand it, since it doesn´t match the Standard and it´s clearly not balanced in dynamic range (for good or for bad).
 
Even with film stock, the rating is merely a recommendation, which is one reason Kodak switched to the E.I. (Exposure Index) label instead of ISO/ASA -- they pick a rating based on what they feel gives you an optimal balance between speed and density for printing. The manufacturer rating number doesn't necessarily correlate precisely to dynamic range or where middle grey falls. Those are factors in determining the E.I. value but not the only ones. There is also some human judgment calls involved.

Plus they round-off to established numbers like 250, 320, 400, 500.

The rating is merely a starting point for exposure.

Now as for why the monitor signal is not exactly matching light meter readings, etc., that's another matter -- perhaps RED needs to refine those in-camera conversions for monitoring to be a little more accurate.

But considering you are talking about only a 1/3 of a stop inaccuracy, it seems to me that it falls into some degree of uncertainty and the realm of human exposure error. In the real world, does it matter if a grey scale is 1/3 of a stop "mis-exposed"?

Also remember that your system is based on Rec 709 monitoring (relative to Rec 709 dailies) -- the signal is brighter for RedSpace monitoring. So it sounds like you are simply questioning the parameters set for the levels of these monitoring outputs and how they match the conversions.

But I would give up on the notion of a precise ASA rating for a camera sensor because there is no such thing, just as there is no precise ASA rating for film stock. All that matters is that you can get your intended exposure to match the monitor output and the later conversions for post. I'd pursue that issue with RED and leave the notion of whether the camera is "really" 250 vs. 320 ASA behind because that can't be resolved.
 
David Mullen ASC said:
Even with film stock, the rating is merely a recommendation, which is one reason Kodak switched to the E.I. (Exposure Index) label instead of ISO/ASA -- they pick a rating based on what they feel gives you an optimal balance between speed and density for printing. The manufacturer rating number doesn't necessarily correlate precisely to dynamic range or where middle grey falls. Those are factors in determining the E.I. value but not the only ones. There is also some human judgment calls involved.

Plus they round-off to established numbers like 250, 320, 400, 500.

The rating is merely a starting point for exposure.

Now as for why the monitor signal is not exactly matching light meter readings, etc., that's another matter -- perhaps RED needs to refine those in-camera conversions for monitoring to be a little more accurate.

But considering you are talking about only a 1/3 of a stop inaccuracy, it seems to me that it falls into some degree of uncertainty and the realm of human exposure error. In the real world, does it matter if a grey scale is 1/3 of a stop "mis-exposed"?

Also remember that your system is based on Rec 709 monitoring (relative to Rec 709 dailies) -- the signal is brighter for RedSpace monitoring. So it sounds like you are simply questioning the parameters set for the levels of these monitoring outputs and how they match the conversions.

But I would give up on the notion of a precise ASA rating for a camera sensor because there is no such thing, just as there is no precise ASA rating for film stock. All that matters is that you can get your intended exposure to match the monitor output and the later conversions for post. I'd pursue that issue with RED and leave the notion of whether the camera is "really" 250 vs. 320 ASA behind because that can't be resolved.
Click to expand...


I totally agree to what you are saying and it´s basically the same thing i tried to explain on the previous post. ISO is the Kodak or Red recommendation. A 1/3 of a stop is exactly the difference between rec709 and redspace LUTs and shouldn´t need any discussion. But the LUT outputs are way off a third of a stop. (1 1/3 of a stop for 709 and 1 stop for redspace) and that´s something a bit problematic for monitoring on camera and on set. Clients/director will complain about seeing the output too dark if you expose for 320ISO and set the same setting on camera.
 
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