Jon Nash
Well-known member
I've been tripped up a few times when I'm shooting a low key situation and want to let the blacks go black without it getting noisey. I'm sure I'm overlooking something fundamental. Any Pointers please ?
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Preserving the blacks without the noise
- Thread starter Jon Nash
- Start date
Björn Benckert
Well-known member
Please anyone, correct me if Im wrong since I had tried to explain how I see those sensors to work with so many DP's and alike and every time it kind of leads to them looking nervous and asking for a calibrated monitor or such...
I think good exposure, dynamics and noise free lowlights are created as follows.
Set your camera at 400 ASA (it's filming raw I know, it's 800iso native I know, but still do it)
Then you make sure that you have enough fill light so that your "red noise" bar on screen does not show at all, not even in your total blacks.
And you also make sure that the highlight texture that you want to keep does not show as red in "the overexposed bar"
Now if your picture on monitor looks good, your blacks are black etc. The above means that you used the top half of the sensor. you tossed some dynamic range away but you have super clean noise free lowlights, something I find more important than using the absolute full range of the sensor.
What's available furthest down in the absolute bottom of the dynamic curve of the sensor is to me not so nice to use it's basically all noise.
An example.
Shooting an Ikea kitchen with black matte wooden cabinets and white walls and burned out windows. Then if you use the full sensor. i.e expose so that the cabinets are on the bottom blacks, right above the noise floor, then you are in trouble if the client want to see the texture of the cabinets or such. But if you are on a lower asa and the picture looks good, i.e. you see some texture there, then you can still reach down and get that extra texture without bringing noise into to the picture.
One thing to remember is that the histogram on screen actually reacts to the asa. I think this is odd, but it does, the noise and over expo bars on the other hand are set to native iso so those are what you need to look at. The histogram is only a histogram of what you see on the screen. If you are on 800 iso then it's a histogram showing what you actually have as exposure on your sensor.... this is a bit of a mind bender I think. It would be more accurate I think if the histogram showed what's there on 800 iso at all times.
When I talk to DOP's about the above they get nervous and tell me they do not like this RED €%#"# and explain to me that the alexa is much better, since what you see is what you get...
Hope I did not make you all confused now..
I think good exposure, dynamics and noise free lowlights are created as follows.
Set your camera at 400 ASA (it's filming raw I know, it's 800iso native I know, but still do it)
Then you make sure that you have enough fill light so that your "red noise" bar on screen does not show at all, not even in your total blacks.
And you also make sure that the highlight texture that you want to keep does not show as red in "the overexposed bar"
Now if your picture on monitor looks good, your blacks are black etc. The above means that you used the top half of the sensor. you tossed some dynamic range away but you have super clean noise free lowlights, something I find more important than using the absolute full range of the sensor.
What's available furthest down in the absolute bottom of the dynamic curve of the sensor is to me not so nice to use it's basically all noise.
An example.
Shooting an Ikea kitchen with black matte wooden cabinets and white walls and burned out windows. Then if you use the full sensor. i.e expose so that the cabinets are on the bottom blacks, right above the noise floor, then you are in trouble if the client want to see the texture of the cabinets or such. But if you are on a lower asa and the picture looks good, i.e. you see some texture there, then you can still reach down and get that extra texture without bringing noise into to the picture.
One thing to remember is that the histogram on screen actually reacts to the asa. I think this is odd, but it does, the noise and over expo bars on the other hand are set to native iso so those are what you need to look at. The histogram is only a histogram of what you see on the screen. If you are on 800 iso then it's a histogram showing what you actually have as exposure on your sensor.... this is a bit of a mind bender I think. It would be more accurate I think if the histogram showed what's there on 800 iso at all times.
When I talk to DOP's about the above they get nervous and tell me they do not like this RED €%#"# and explain to me that the alexa is much better, since what you see is what you get...
Hope I did not make you all confused now..
Nick Gardner
Well-known member
I shoot at iso 1600 and get nice clean blacks all the time. You don't have to over expose to get clean blacks. Black is the absence of light right? you can't over expose that. You have to add a curve and bring the black levels down to where they should be. All other cameras do that for you, you need to do it yourself with red footage. Either do it after the fact with a CC tool, or set up the contrast in the camera so that you have some, or copy a curve from redcine onto your camera. Look at this -
http://vimeo.com/23729731
Plenty of crunchy blacks, no noise. The interior was probably shot at 1200 iso.
Nick
http://vimeo.com/23729731
Plenty of crunchy blacks, no noise. The interior was probably shot at 1200 iso.
Nick
Zeb B
Well-known member
Raw Preview is WYSIWYG on histogram . . . no? I shoot at 320ISO and keep just under clipping on the highlights - seems to give the widest DR. After that, if the scene is beyond the DR of the sensor (or film for that matter) then you need to fix that before shooting. ND film on the exterior windows, fill light etc - balance the scene for maximum DR before turning the camera on. A spot meter is useful here.
Some of the greatest DP's come from the lighting world since that's where the magic starts. A RED is just a recorder of the lighting scene you have designed. If it's shit - then the RED will record that in brilliant 5K
Some of the greatest DP's come from the lighting world since that's where the magic starts. A RED is just a recorder of the lighting scene you have designed. If it's shit - then the RED will record that in brilliant 5K
Björn Benckert
Well-known member
I understand the Raw preview. and just I my theory you shot with a lower asa. So I think we think the same.
Zeb B
Well-known member
Yes . . . except I don't like Kalles kaviar on knackebrod
Björn Benckert
Well-known member
What I mean is if you now would like to have texture where you have crunch blacks... then that would not really work, since you shot the blacks as black... So when lighting a scene it's better to have enough fill so the bottom of the sensor is not in use. Then you can gain up and you have noise fee texture in your blacks. If you use the full range of the sensor then your blacks are black and there is not much you can do to bring light to them after you left the studio.
And I don't mean at the level of noise visible on vimeo I mean noise on full 4k or such.
Zeb B
Well-known member
I think there are some who just shoot whatever then crush the blacks in post to mask the noise. That's a crap approach to cinematography
Shane Kelly
Well-known member
I think that dropping he compression rate when shooting a scene with lots of black would also help.
Scott Crawley
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It should, so long as there is an adequate exposure with which to work. If you are below the noise floor to start with don't expect it to help you. Lower compression will make your image more elastic in post, but it will not enable you to pull a clean image from a light starved sensor.
jan meric
Well-known member
Gunleik Groven
REDuser Sponsor
Without digging into the "the cam is really XXX ISO" thingy, you really need some contrast in the image to get smooth blacks. Even more important under tungsten.
Low contrast + low light = noisy blacks, and if you contemplate and meditate over linear light for a while and mapping of stops to bits, that becomes really quite logical.
G
Low contrast + low light = noisy blacks, and if you contemplate and meditate over linear light for a while and mapping of stops to bits, that becomes really quite logical.
G
It depends if you want clean detail in the shadows (then they must be exposed above the noise level, then level adjusted in post), or it's OK for the shot intent to have them be truly be close to inky black (in which case, noisy shadows don't matter as you can crush them in post).
As Gunleik suggests, tungsten can be more problematic as it starves the inherently noisier blue camera channel, potentially leading to underexposing blue causing visible blue noise. This is less of a problem from the original Red M sensor, but still a factor in any silicon sensor.
As Gunleik suggests, tungsten can be more problematic as it starves the inherently noisier blue camera channel, potentially leading to underexposing blue causing visible blue noise. This is less of a problem from the original Red M sensor, but still a factor in any silicon sensor.
Will Keir
Well-known member
Nick Gardner
Well-known member
Really beat up 1.5" speed rail actually. Lots of pits and divits in it ;-) I plan on making a new lightweight version with 1.5" CF tubing and a CF honeycomb cored mitchell base for run and as soon as I get a minute.
Nick
Nick
Gunleik Groven
REDuser Sponsor
Nick is onto an important point: Decide what (if any) of the image is really black on set. Stick to that!
Redgamma is a really hard S curve applied in camera that pushes stuff out both in the top and the bottom and which I don't really like and still is the only option on the R1 MX BUT it has the adavantega of visually forcing your exposure towards "the middle" of the sensors theoretical/mathematical DR, where the MX is best on the RedOne (The practical DR on the Epic Scarlet is much wider for a number of reasons).
In a way, looking at RedGamma, you kind of are forced to protect both your highlights and lowlights, which gives you the option to pull out some nice gradients in the lowlights in post, if that is what you want AND you didn't expose at 1600, which for all practical matters is 2,25 stops under the calibration level of 320/5600.
Best thing, though is to not interpolate too much what is available in post (on Epic/Scarlet) anfd just get as far and close as you can get to what you want on set. Use lights!!! And Shadows and good monitoring and make decissions as to what you want to see and what you want to let go. Stick to them. That is the best advice I can give for getting smooth blacks...
Anyhow: Trying to make hgh contrast from low contrast and underexposure equals noise, no matter colortemperature...
Redgamma is a really hard S curve applied in camera that pushes stuff out both in the top and the bottom and which I don't really like and still is the only option on the R1 MX BUT it has the adavantega of visually forcing your exposure towards "the middle" of the sensors theoretical/mathematical DR, where the MX is best on the RedOne (The practical DR on the Epic Scarlet is much wider for a number of reasons).
In a way, looking at RedGamma, you kind of are forced to protect both your highlights and lowlights, which gives you the option to pull out some nice gradients in the lowlights in post, if that is what you want AND you didn't expose at 1600, which for all practical matters is 2,25 stops under the calibration level of 320/5600.
Best thing, though is to not interpolate too much what is available in post (on Epic/Scarlet) anfd just get as far and close as you can get to what you want on set. Use lights!!! And Shadows and good monitoring and make decissions as to what you want to see and what you want to let go. Stick to them. That is the best advice I can give for getting smooth blacks...
Anyhow: Trying to make hgh contrast from low contrast and underexposure equals noise, no matter colortemperature...