R3D sample: Folks with more RED experince than I please weigh in on noise performance

[Timur Civan]

http://timurcivan.com/downloads/R3Dtest.R3D

RED Scarlet: Canon 50mm F1.8, Tungsten soft box with 1/2 blue CTO to boost the blue channel, and help balance the color channels.

I shot this exposed for ISO250.

This is taken post black shade, after the camera warmed up and acclimated for over an hour in a hotel room. Camera temperature was 50C , Fan in standby was set to 50%, to make sure it calibrates at the same temperature it reaches while running.

This is my Camera assistant sitting in for a lighting test. The color is accurate.

After a black shade, and shooting at 250 i feel this image has a lot of noise that just shouldn't be there.

I'm trying to narrow down the cause. Does this look normal to you? I am trying to figure out if this kind of grain is consistent across scarlets or if perhaps something is wrong with my particular unit.

Can someone post a grab shot @ 250 iso with a similar range of dark subjects so i can compare the grain structure ?

thank you gentlemen.

 

[Bob Gundu]

It's hard to say without seeing a clip, but this looks good to me Timur.

 

[Timur Civan]

im rendering out thorugh RCX right now. will post up 2-3 seconds in a few.

 

[William Robinette]

Interested in seeing a clip as well. I'll say though (and not being the most experienced user here, still figuring stuff out myself) playing with it in REDCINE-X PRO it looks about what I would expect from my Scarlet. Something I am finding for as wonderful as raw is, in these situations it takes a bit of massaging to really make it shine. A tiny bit of de-noising and sharpening goes a long way.

 

[Bob Gundu]

Also, are you using the latest RCX? A few days ago I was getting nasty sensor patterns in my footage. I opened a non-beta build of RCX and it wasn't there. I rebooted version 12 of RCX and for some strange reason the sensor pattern was gone. I'm just wondering if there may be any graphics issue with your computer.

Bob

 

[Matt Ryan]

curious why you chose 250 as your ISO? Going under 320 does nothing image wise....unless you were just using it as a metered exposure

 

[Timur Civan]

The scene measured in at 10 or so stops, so losing a stop up top wasnt an issue. I wanted to see how "clean" it can go. I usually shoot between 320-800.

I;ve seen some folks getting amazing results up to 2000... trying to figure out how they do that...

 

[Timur Civan]

Also, are you using the latest RCX? A few days ago I was getting nasty sensor patterns in my footage. I opened a non-beta build of RCX and it wasn't there. I rebooted version 12 of RCX and for some strange reason the sensor pattern was gone. I'm just wondering if there may be any graphics issue with your computer.

Bob

Oh. This i have not tried. Whats the most stable version?

 

[Bob Gundu]

I been using all the betas. Been really stable for me.

Oh. This i have not tried. Whats the most stable version?

 

[William Robinette]

Timur, I'm very interested in having a discussion about this.

As far as I can tell, everything with regards to RED and ISO in relation to exposure is backwards from what we assume. I've started shooting at 320 indoors and 800 outdoors, exactly opposite from what you think you would do. Bringing it down to 250 ISO isn't cleaning up the image at all in terms of noise from the sensor, it just affects your exposure decisions because it changes the monitoring exposure path. I've started living and dying by the histogram and the goalposts. If you bring your R3D into REDCINE, your histogram is still crammed against the lower end of the scale. I would imagine exposing even a stop over what is "correct" for this image and bringing it down in post is going to get rid of a lot of that noise.

I'm interested in hearing more about this...

 

[Matt Ryan]

Timur, I'm very interested in having a discussion about this.

As far as I can tell, everything with regards to RED and ISO in relation to exposure is backwards from what we assume. I've started shooting at 320 indoors and 800 outdoors, exactly opposite from what you think you would do. Bringing it down to 250 ISO isn't cleaning up the image at all in terms of noise from the sensor, it just affects your exposure decisions because it changes the monitoring exposure path. I've started living and dying by the histogram and the goalposts. If you bring your R3D into REDCINE, your histogram is still crammed against the lower end of the scale. I would imagine exposing even a stop over what is "correct" for this image and bringing it down in post is going to get rid of a lot of that noise.

I'm interested in hearing more about this...

thats why I was curious in his choice of 250ISO. You are effectively sliding your middle grey very low causing the DR on the low end to get scrunched... If you would have exposed at say 800 or even 640 or 500, you could have then brought the image down to reduce the noise. Now that you have basically underexposed dramatically, bringing the image up will cause more noise than if you shot at say 800 to begin with. Evin Grant isn't blowing smoke when he advises everyone to keep the camera at 800ISO, theres a reason for that.

 

[Timur Civan]

http://timurcivan.com/downloads/TEST2.R3D

But isnt that what rating the cam at 250 is doing? "Over exposing the native 320".

I mean, take it up to 800 ISO, and see what it looks like. Its about a stop over exposed @800, and it looks really grainy.

This is what im trying to figure out. Graeme?

 

[Matt Ryan]

going under 320 is not changing the image the camera captures, only the monitoring.

 

[Bob Gundu]

If you ask for Graeme, you're using one of your "call a friend" lifelines.

http://timurcivan.com/downloads/TEST2.R3D

But isnt that what rating the cam at 250 is doing? "Over exposing the native 320".

I mean, take it up to 800 ISO, and see what it looks like. Its about a stop over exposed @800, and it looks really grainy.

This is what im trying to figure out. Graeme?

 

[Matt Ryan]

because you have to crush the blacks back down to what they were exposed for... That's what I mean, you have crushed your lower end on the grey scale which relates to faster clipping on the high end and more noise in the darks when you try to boost the image.

 

[Matt Ryan]

just as a test shoot the same shot with in camera setting of 800 and expose for that, see what you get

 

[Tom.Wong]

either way, effectively EXPOSING for a lower iso should reduce the noise because you are feeding all your shadow areas more light, and monitoring at that lower iso where it's dark it should stay dark. you shouldn't be seeing any noise from the darkest portions of the image unless you start gaining it up in post. while your more shadow detailed areas should be a lot cleaner because you are putting a lot more light there to be able to see that detail.

so if he is still seeing noise and exposing for a low iso, I think there might be issue worth concern.

 

[Matt Ryan]

I'm not seeing any noise at 800ISO, but even at 800ISO the shot is underexposed...the histogram is bunched on the lower left side without any curves or contrast added...
here it is at 800ISO:

and here is a tiff at 800 ISO out of RedcineX Pro B13:

Here it is at 200ISO with no curve or contrast added:

with a bit of crushing and some slight noise reduction this shot is fine.

 

[Timur Civan]

just as a test shoot the same shot with in camera setting of 800 and expose for that, see what you get

But isnt that the point of raw, by moving the slider to 800ISO, after "exposing" @ 250 is the same as over exposing 800 and bringing it down. I should be getting a nice bright clean image @ 800, albeit over exposed, then by dropping it to 250, getting a super clean black. perhaps we are saying the same thing just in different words.

Tom did you DL the shot? what does your magical OLED say?

 

[Timur Civan]

I'm not seeing any noise at 800ISO, but even at 800ISO the shot is underexposed...the histogram is bunched on the lower left side without any curves or contrast added...
here it is at 800ISO:

and here is a tiff at 2000 ISO out of RedcineX Pro B13:

It does NOT look like that coming out of RCX pro on my computer....... Wow....

OK, so i gotta trouble shoot my computer perhaps?