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Getting Dramatic Scenes Without Noise in the Picture


Michael Hammond
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Hi everyone, 

 

First post here! I have a question about getting dramatic lighting without noise in the shadows. Here's the hypothetical:

Say I'm going for a dramatic scene, lots of shadows. And let's also say the talent includes one person in the scene, sitting in a chair in a dark room. There are a couple of practicals in the scene so there's going to be more light than just a key and key/fill on the talent's face and body. 

I'm using a 2.8 lens and I don't want to shoot wide open so I decide I'm going to key the actor at a 4.0. I set my lighting to do so, set my iris to 4.0 and viola - talent looks nice with an overhead softbox with a grid shining light down on them, and on their area only. 

Meanwhile, other areas in the scene that aren't filled with practicals and their accompanying ambient light (which isn't much compared to my overhead softbox) goes into deep shadow. Well, there's the look I'm going for but now those areas are underexposed. And now there's going to be noise in the shot in those areas. 

I can increase the light output of the overhead softbox and the practicals to get more light to the sensor. But to keep the talent at the right exposure I need to stop the camera down so all that additional light is basically going back to the same levels with some underexposure issues happening due to a larger f-stop.

Is my recourse going to be using more light for a clean shot and then darkening in post? As long as my ratio of key to practicals to shadows is where I want it, this should work? And if the scene is in a larger room than in my attached example (more space in between the light sources) would I add something like an ambient fill above the scene and then darken in post?

In the attached jpeg of a quick and dirty setup, I'm at a 3.2 f-stop with a 2 stop ND filter. 

Thanks for any feedback on this! 

Bed.jpg

Edited by Michael Hammond
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Sure if you increase the light level but stop down the lens, the sensor is getting the same amount of light so the noise is the same.  But if you increase the amount of light and lower the ISO rating of the camera instead of stopping down the lens, then the sensor will be getting more light and the noise will be lower, but now you have to control your brightest highlights more to keep them from clipping. It's generally a trade-off between noise in the shadows versus more detail in the bright highlights.

There isn't necessarily more noise just because you have dark shadows. I mean, if you had white titles on a black background, would the black background be noisy?  You work at an ISO setting that gives you the general noise level you like and then light for whatever mood you want, just watch out for clipping, and then don't lift the shadows later in color-correction.  If anything, if you are worried, then add slightly more fill and then crush the shadows a little bit in color-correction.  But the main thing is to avoid lifting anything.

And don't judge noise by looking at the log image, but with the display gamma applied. A certain amount of noise goes away when the correct display gamma is applied.

And lighting a room is more than just lighting the actor.  If you want to shoot at an f/4, then you light the room to look the way you want at f/4.  If a practical lamp is too dark, then put the next higher wattage bulb in it. If the perimeter of the room is falling off too quickly to darkness, then bounce a little light into the ceiling or something to bring up the ambience.  But don't be afraid of mood or shadows.

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Thanks very much David - you bring up some really good points. Specifically to remind me that there's always a trade-off when it comes to lighting. When we change one thing accomplish something we want, and then we need to change other things to work with that decision. 

Your answer about white and black tiles brings up a related question I have about camera sensors.

Generally speaking, when it's said that we need to expose for the sensor we're talking about giving that sensor enough light to be clean - or as clean as possible if that's the look we're going for. If we expose for the white tiles, the black tiles are going to fall below what we might think of as an acceptable exposure level. Why wouldn't that give noise in the black tiles? Is it because we're giving the sensor an overall amount of light and therefore it has enough info to work with for the entire picture?

Asked another way, if I film a black room with no light the image is going to be FPN, and all sorts of terrible electronic noise. If I shot a well lit white room the picture will be very clean. When I mix these two in a scene - a well lit person, and areas where very little light is present in order to get dark shadows - why wouldn't the dark areas get noisy? Especially if I light close to a 2.8 for a 2.8 lens.

 

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There’s no reason for a black curtain or wall or shadow to be noisy just because it is black unless you are working at a higher ISO. Put the lens cap on your digital still or video camera and record something. If black is noisy then you are working at too high an ISO.

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I think if you've correctly exposed your subject actor in light that portrays them as you like, the shadow areas behind will be dark.  They will not be noisy... unless you try to make the shadows brighter in the color correction.  So if you want dark shadows, they are not under exposed, they are correctly exposed to show as dark shadows.

If you're in doubt, and you are using a camera with good dynamic range, you can do as David suggests and shoot at a lower ISO setting and you should have enough range still in your highlights to avoid clipping.  I sometimes do this when I want to show, on set, a dark rendering of the scene, but... I'm concerned that the director will, in the end, prefer a lighter rendering during the color correction phase of production.  For example, if I shoot at ISO 400 instead of my usual ISO 800, I will be able to lighten the scene by one stop without introducing more noise than if I'd shot at ISO 800.

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That is one of the problems with digital. It tries hard to make sense of the shadows it can't reproduce well and it = noise. That is where film had an advantage. All you can do is to do lots of experiments to see what works best. 

OP, your sample is flat, no deep black's or even half ass blacks. See what you can do in post. As I said, do all sort of experiments.  The late Robby Müller said he did weeks of experiments before shooting Down By Law. But post can only do so much. It has to be a balance with camera and post.

 

Bed.thumb.jpg.05721d43c914ccbf17afde3f331bdd38-3.jpg

Edited by Daniel D. Teoli Jr.
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Gordon 'Godfather' Willis was not only the man who shot the Godfather. He was the godfather of bringing chiaroscuro to modern movies. They had chiaroscuro back in the noir days with their beautiful BW films. But Willis brought it up to date with color.

 

 

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I would question the notion that film has cleaner blacks than digital — film grain in the shadow region (the toe) is usually larger than shadow noise in most digital cameras, and this grain limits how far you can bring up detail with a film image compared to a digital one. Film negative’s latitude is primarily in the overexposed regions where digital is weaker. The fact that some digital cameras can shoot at 3200 ASA and higher compared to film is an example of the lower noise floor with digital.

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It gets confusing to mix up the technical issue of noise or grain in blacks versus the artistic issue of how much contrast or mood to put into the lighting. Not every movie has to be lit like “The Godfather”.  But this technical issue of shadow noise comes up all the time and I think it’s because people are either working at too high an ISO setting for good blacks and/or have color-corrected the image with lifted blacks. If the scene has low noise in general, there is no reason why a dark shadow should have more noise any more than the noise should jump up when the character turns out the lights in the room or enters the scene in a black coat. Unless the camera is on auto-gain or something.

Shoot a grey scale and select an ISO setting that gives you a noise level you can accept and then light the scene with as much mood as you want. Just don’t change your mind in post and try to lift the shadows, or use the wrong display gamma and end up lifting the blacks.

It’s true that noise is made worse-looking by compression schemes. 

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1 hour ago, Daniel D. Teoli Jr. said:

That is one of the problems with digital. It tries hard to make sense of the shadows it can't reproduce well and it = noise. That is where film had an advantage. All you can do is to do lots of experiments to see what works best. 

OP, your sample is flat, no deep black's or even half ass blacks.

The blacks look normal on my monitor, nothing looks lifted. 

When digital cameras have problems with reproduction of shadow detail, the artifacts you see are due to compression. Noise isn’t the result of a sensor trying to “make sense” of information, you’re describing a processor trying to compress information. Noise is just due to signal amplification.

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Thanks for the replies everyone. 

David, your example and suggestion of shooting with a lens cap on made this perfectly clear for me. I guess I've been assuming that a camera is going to see dark and say to itself "say, I really need to see that." Of course cameras have no creative brain so they shoot what you give them. I thought about the times I've done an ABB with a lens or body cap on and watching the camera level out for the ISO it's set at. And then when it's done I have a nice clean image.

So I went back into the same room with the one light and turned everything else off, watched the LUT in my screen and then applied it in post. No noise in the shadows.

Thanks again and I'm no longer scared of shadow! 

Edited by Michael Hammond
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1 minute ago, David Mullen ASC said:

When digital cameras have problems with reproduction of shadow detail, the artifacts you see are due to compression. 

Absolutely understand that. In fact, I'm just now moving from an 8-bit 4:2:0 highly compressed AVCHD camera to a new camera that gives me 10-bit 4:2:2 prores. I think in the past I've run into exactly this problem of compression which, I think, is more amplified in shadows. That's the way it seemed to me. 

So with this new camera I find that I can expand my opnion about light and shadow in the same scene. 

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2 hours ago, Daniel D. Teoli Jr. said:

OP, your sample is flat, no deep black's or even half ass blacks. See what you can do in post. 

Bed.thumb.jpg.05721d43c914ccbf17afde3f331bdd38-3.jpg

Hi Daniel, can you tell me what you mean by "flat?" To me, there are areas of light (where I'm sitting and where the practicals are) and some shadow (walls to the right and left of me, artwork above bed. Plus there are a couple different colors here.

To be honest, I do often think my shots are flat and I'm trying to get better at that, but I think this one has a little depth. 

Edited by Michael Hammond
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A little noise in itself isn't so bad as texture, just like film grain isn't so bad... but macro blocking of noisy shadows due to heavy compression is quite terrible. 8-bit creates problems of banding with gradients, 4:2:0 creates problems of sharpness/detail in flat areas of color, but compression is the third component to watch out for.

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