CMOS sensor

[Peter Lyons Collister, ASC]

Thanks Eric and others. Mark I think you misunderstood my question. This has nothing to do with RAW and meta data. It has to do with the intrinsic sensitivity of CMOS sensors to Red Blue and Green.

[Filip Orlandic]

Aren't all CMOS sensors ( Alexa, Canon, etc) balanced to 5000 degree kelvin light????
Peter

Mysterium 5000K
Mysterium-X 4300K

[Gunleik Groven]

Mysterium 5000K
Mysterium-X 4300K

????

Would kind of explain WB oddities I sometimes see bellow 4400k, though, but I'd have thought it was closer to 5000+...

Would've been fun to know.

From where did you pull this?
I'd be surprised if this was really totally accurate.

As tro Mark. It is (in some circumstances) not irrelevant. At some WB the sensor response is "flat". The further beyond that you go either way, the more post-processing is done to ballance the image data. Some of that processing can be good. Some, not so much.

If it looks good, it's fine.
If you run into issues, it is good to know...

[Filip Orlandic]

????

Would kind of explain WB oddities I sometimes see bellow 4400k, though, but I'd have thought it was closer to 5000+...

Would've been fun to know.

From where did you pull this?
I'd be surprised if this was really totally accurate.

As tro Mark. It is (in some circumstances) not irrelevant. At some WB the sensor response is "flat". The further beyond that you go either way, the more post-processing is done to ballance the image data. Some of that processing can be good. Some, not so much.

If it looks good, it's fine.
If you run into issues, it is good to know...

It was said before that it's between 3200 and 5000.

I will try to find the original post.

[Gunleik Groven]

It was said before that it's between 3200 and 5000.

Hm... It's NOT close to 3200.
From what I see, I'd say 5000 at its lowest.

Just do a wb test and see where the response is flat and where you introduce gain and clamping (in the red and blue channels respectively).

The M was re-rated from 5600 to 5000 @ B30. But if that is really "clean" response... I am not sure.

Nice way to verify, is to look at plates from the R, G & B channel from the same image at different WB settings.
Expose a couple under tungsten/Daylight and peek at the separate channels to look at exposurelevels and noisegeneration at a given WB rating, look at the RGB waveforms, and I guess you'll get a hunch...

A lot of stuff has been "said" at various points.
Like "RedSpace is the best for everything". :)

Run tests, and make up a qualified opinion. Then choose, and check that what you've chosen actually works...

That the MX has better lowlight sensibility than the M, makes it less prone to tungsten noiseissues, as you have some extra headroom in the blue channel, and by slightly using that headroom in the lower range, to gain some headroom in the top in the RED by underexposing it 1.25 stops in the top (by shooting @ 800 ISO), thereby avoiding hard clamping in the RED channel @ tungsten is all good.

BUT it is not the same as saying that the flat response is close to 3200.

It's more of a philosophy thing as to what settings that averagely will give the most good results for the most users.
WHICH I BTW think is a perfectly good reasoning and a totally legitimate point for an advice.

Like RC3/RG3 will work "out of the box".
Mostly true for many applications, and probably the most of the userbase most of the time.
So listen.
The advice is good. If not arguably from a purely technical standpoint allways true. It is "true enough".

Edit:
I am a bit wary about publishing tests like these, these days, as they are easily interpreted as "stuff is noisy" or "not right"
I think they are good for a totally different purpose:
To see how a signal chain performs and learn to use and master it.

I am not saying there is anything wrong with it.

But as it is too often interpreted as such, I have leant more and more towards suggesting ways to realitycheck statements, rather than publishing images to state a point...


:)

[Peter Lyons Collister, ASC]

My original post stems from often reading about "noise" issues shooting Red MX under tungsten lights without any wart ten 80 filtration. I have read about these issues for Alexa or Nikon or Canon DSLRs.
We shot 80 percent of Spiderman under tungsten lights and have run tests to IMAX and it seems pretty clean.

[Scott Crawley]

I recently did a series of readings to find and compare the noise threshold of Scarlet under daylight and tungsten at several apertures. I found that under tungsten light i did indeed run into noise sooner that under daylight, though for the most part it wasn't that significant. At stops between f5.8-f8 the difference in light levels ran from 12-25 fc, to rephrase; I needed 12-25 fc more tungsten light to get an image as clean as with a daylight source. So for most shooting it would seem that just walking your tungsten lights in a couple feet would compensate... If I understand my results correctly.

EDIT: corrected Lux to read fc

My original post stems from often reading about "noise" issues shooting Red MX under tungsten lights without any wart ten 80 filtration. I have read about these issues for Alexa or Nikon or Canon DSLRs.
We shot 80 percent of Spiderman under tungsten lights and have run tests to IMAX and it seems pretty clean.

[PatC]

I think a lot of tungsten "noise" arguments come from the original M sensor and it has been much less of an issue moving into R1MXs and EPICs.

[Gunleik Groven]

Silly me. I don't even have much noise from the M... :)

[Sidney L. Plaut]

My original post stems from often reading about "noise" issues shooting Red MX under tungsten lights without any wart ten 80 filtration. I have read about these issues for Alexa or Nikon or Canon DSLRs.
We shot 80 percent of Spiderman under tungsten lights and have run tests to IMAX and it seems pretty clean.

The reason being you prob. didn't need to push the sensor by underexposing it - you prob gave enough exposure in the shadows and brought them down in post? - only speculating of course:)

An easy test is to put the body cap on. crank up the ISO to 3200-12800. press "video/false colors" and change the white balance. You will see a difference in the shadow exposure depending on
which White balance you set. - the exposure of the right half or left half of your sensor can be noticeably different.

With build 3x it has much improved and you prob won't see a difference below iso2000 depending on your sensor temp.

- Edit : since redgamma 3 crushes the blacks a bit it is easier too see in RedGamma2.