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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 :)

help pls noisy shadows

david farland said:
Just wondering if these RGB histogram outputs are typical for other people with the lens cap on.

48_1206848008.jpg


Cheers,

Dave
Click to expand...

Dave, are you sure those aren't the Luma Histograms? I can't tell by the photo if they're white or just blown out. My luma graphs look almost identical to yours with the body cap on. RGB looks quite a bit different for me.
 
your right....they are luma hist graphs.
As you probably know the RGB graphs look similiar over the asa range so I won't display.
thanks very much for for the feedback...Dave
 
I have the same problem with preview out. A lot of vertical noise and chromanoise in the black and dark grey under normal exposure in day light and 4300k.(320asa). I did the black shading and it was still the same.I saw the noise in redalert and redcine but when the R3D files got into Scratch the noise was gone. Strange??
 
david farland said:
Just wondering if these RGB histogram outputs are typical for other people with the lens cap on.

48_1206848008.jpg


Cheers,

Dave
Click to expand...

hi there,

yes i get similar looking histograms which i think show a very high base level of noise. i sent an r3d clip of black to the guys at red (who were doing their level best to be helpful and considerate to my panicked state of mind) which i thought was simply a mess (the camera clearly has no idea what black is) and they said it was within "normal tolerances".

if you had this kind of noise when recording audio, the signal to noise ratio would render the audio unusable unless you were recording a rock concert....

surely if the camera is properly calibrated then the histogram should be a single spike with the lens cap on rather than a mountain-like peak...?

surely we must be able to tell the camera what black is or what's the point of doing a (or in my case about a dozen) black shading?

i understand that r3d files need processing, but my dslr has infinitely (well several thousand asa i guess) less noise in the blacks than my red.

AM I WAY OFF BASE HERE?

cheers,

david

p.s. by the way, red offered to send a replacement camera to me in the philippines at very short notice - the only problem being that if my camera turned out to be "normal", i would have to pay for all the shipping.

obviously in an ideal world i would have had the camera for some weeks before a shoot in the back of beyond, but in this case that just wasn't possible. i should have turned the shoot down because i was so unsure of the camera (and its brand new underwater housing), but just couldn't resist the opportunity to get out of london. never again......
 
Just did a check with my camera and get about the same histograms with the cap on. Yet I wouldn't consider my camera noisy.

From my limited tests comparing the RED to a D200 I would say they have similar noise at the same iso settings. The difference being that at high iso compression makes the noise blotchy on the RED which makes you loose detail so I would give the D200 some advantage there. Hopefully build 16 will help in that aspect.

David, can you post some pics or quicktimes?
 
I was concerned about noise in the shadows too, but that was at 32k, at WB of 5k
wide open, with asa at 320 there is no objectionable noise, I lit a scene with one 150 and
the blacks were nice.
 
There is no absolute black. Theoretically, with every bit of information you get another stop of resolution but "absolute black" will never be reached. And noise will step in somewhere. Therefore the RED ONE preserves its noise floor. It's up to the colorist in post to decide where he wants to set the black level.

So no need to panic about this histogram. It's good that the camera doesn't clip the deepest shadows.
 
big lebowski said:
There is no absolute black. Theoretically, with every bit of information you get another stop of resolution but "absolute black" will never be reached. And noise will step in somewhere. Therefore the RED ONE preserves its noise floor. It's up to the colorist in post to decide where he wants to set the black level.

So no need to panic about this histogram. It's good that the camera doesn't clip the deepest shadows.
Click to expand...

I agree. However I think it would be nice to have the 'option' to move the bottom point where the sampling starts slightly higher up. Maybe cut into the noise a little? My reasons for thinking this is that it may make life a little easier for the codec and your are unlikely to be able to use the detail at the very bottom without temporal noise reduction.

Michael
 
I think it would be better if RedCine would give you a nicer image to start with rather then this flat image with all the noise exposed. It might be correct from a technical point to let you see everything that is in the file but it always needs correction and it might confuse people.
 
sander kamp said:
Just did a check with my camera and get about the same histograms with the cap on. Yet I wouldn't consider my camera noisy.

From my limited tests comparing the RED to a D200 I would say they have similar noise at the same iso settings. The difference being that at high iso compression makes the noise blotchy on the RED which makes you loose detail so I would give the D200 some advantage there. Hopefully build 16 will help in that aspect.

David, can you post some pics or quicktimes?
Click to expand...

this is all very interesting...

best thing to look at would be an r3d shot with the lens cap on....? where/how should i upload it please?

i looked at some proxy files that i shot in low light and you can't see any noise in the blacks - seeing as how they are merely instructions (?) for how QT should see the raw file, it must just be a matter of gamma/processing.

having said that, i still don't understand the histogram with the lens cap on - point being that i would have thought that there IS such a thing as absolute black - or you should at least be able to tell the camera what it is......?

if there's zero light hitting the sensor, is that not absolute black?

i very much appreciate everyone's input,

david
 
big lebowski said:
There is no absolute black. Theoretically, with every bit of information you get another stop of resolution but "absolute black" will never be reached. And noise will step in somewhere. Therefore the RED ONE preserves its noise floor. It's up to the colorist in post to decide where he wants to set the black level.

So no need to panic about this histogram. It's good that the camera doesn't clip the deepest shadows.
Click to expand...

trying to get my head round this - surely zero light is absolute black and you should be able to tell the camera that this is the case.

i think i understand your point about resolution, but again shouldn't it be possible to tell the camera at which point there's nothing more to see?

thanks for your thoughts,

david

p.s. i'm no longer panicking about the histogram, just mildly hyperventilating
 
dmig said:
trying to get my head round this - surely zero light is absolute black and you should be able to tell the camera that this is the case.

i think i understand your point about resolution, but again shouldn't it be possible to tell the camera at which point there's nothing more to see?

thanks for your thoughts,

david

p.s. i'm no longer panicking about the histogram, just mildly hyperventilating
Click to expand...

Of course there's absolute black in the real world. But no sensor (or film for that matter) comes even close down to this level. The low end of the sensor consists of the noise floor and usually you want to set your black level somewhere in there. But there's no way for the camera to tell where exactly you want it to be.

For the preview outputs of the camera (and also for the metadata recorded with your r3d) you may want to lower the brightness level in the camera's video settings.
 
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