Low Light Exposure Process help

[Noah S]

Hi all,

I am a fairly new DP and would love to get some advice on exposing properly in low light situations.

Here is the scenario: (Red Scarlet X)

So we had a musical artist standing in front of a mic. We wanted it to be fairly moody, simple, and not too bright. I lit her to my eye on what I thought looked nice. I then looked at my Red monitor and I like how that looked there at ISO 800. BUT when I looked at my goal posts I was clipping to the left quite a bit. I was all the way open because I wanted the depth and didn't really want to add more light on her or the background. I did boost the ISO a bit to see if that would help but the difference was minimal on the goal posts. So I ended up leaving it and hoping the noise would not be too bad with the low light.

Here is a link to the finished video.

https://www.youtube.com/watch?v=nw_fJGRdihk

I ended up getting a bunch of noise in the background but I applied some heavy Denoiser which helped clean it up quite a bit. What could I have done better here? Do you guys have a process for these low light situations? How do you not clip your left goalpost IF the goal is a moody darker atmosphere?

Thanks!
Noah

 

[James Falco]

It is ok to clip. When it clips its means its solid black. As long as your subject is at the exposure you wanted it to be.

///

 

[Martin Facci]

It's really hard the judge video quality after the Youtube compression... What i can see (probably cause by the noise reduction) is a heavy banding that breaks apart.
You can see it mostly in the close up shot on the guitar amplifier on her right.

If this is cause by noise reduction i'll probably keep the noise over that banding
Another way will be reducing less noise and also apply some film grain wich removes a lot of banding.

Exposure wise... I think you have it really spot on, i like the overall look.
If you want to have a little more information on your blacks (And this is just my opinion) you could have expose it one stop up and then with color grading take everything down a little but the blacks.
And i would do it with ISO, since HIGHER numbers of ISO give you more range on your dark tones.

Also in color grading, just limiting your blacks to be over pure black (IRE 0) goes a long way.
Of course you won't get any information but it gives you that "washed film look" that a lot of times works better than pure crushing blacks.

 

[Ignacio Aguilar]

If you want the cleanest images, a classic approach to that is to use a lower ISO (320-400 is fine) and then expose accordingly to what you see on a calibrated monitor, waveform or exposure (video check) tools of the camera itself. If you lower the ISO and avoid clipping, what you get is a richer exposure, with more tonal gradations, better color and less noise, since a lower ISO implies a wider aperture on the lens or more light on your subject. Once you are in post, if you have a more balanced histogram, you can fine touch your exposure in color correction, rather than arrive there with an image which is already dark, but also noisy because not enough light reached the sensor.

Of course, it's possible to expose to the same look you're after, but then exposure becomes trickier and you have to be much more precise. So in general terms, it's easier and safer to lower the ISO, and thus actually overexpose the sensor about 2/3 of a stop, specially when you have at your disposal the lights and equipment required to do it.

 

[Joel Arvidsson]

I agree on 320-400 iso for mody shots. Then you have a little room to bump up the shadows in post if you need.

 

[Tom Van]

It's really hard the judge video quality after the Youtube compression... What i can see (probably cause by the noise reduction) is a heavy banding that breaks apart.
You can see it mostly in the close up shot on the guitar amplifier on her right.

If this is cause by noise reduction i'll probably keep the noise over that banding
Another way will be reducing less noise and also apply some film grain wich removes a lot of banding.

Exposure wise... I think you have it really spot on, i like the overall look.
If you want to have a little more information on your blacks (And this is just my opinion) you could have expose it one stop up and then with color grading take everything down a little but the blacks.
And i would do it with ISO, since HIGHER numbers of ISO give you more range on your dark tones.

Also in color grading, just limiting your blacks to be over pure black (IRE 0) goes a long way.
Of course you won't get any information but it gives you that "washed film look" that a lot of times works better than pure crushing blacks.

You'll have more range in the blacks if you lower the ISO. Of course that means you have to provide the sensor with more light

 

[Noah S]

Thanks guys. This is great and a much different approach then I would have done. I am looking forward to testing it out.

So basically for those moody low light scenes...lower the ISO to around 400 and add more light to compensate. It seems it would be best at this point to avoid clipping on the left of the goal post. Do you ever let it clip?? I assume clipping would still give you a noisy image.

 

[Ignacio Aguilar]

I try to avoid clipping of both sides of the histogram (left equals noise, right clipped highlights). But now and then it's unavoidable. You just have to try to put everything in balance in your mind and decide what are you exposing for (it depends on the kind of shoot that you're doing... products, clothes, food, fiction: comedy, drama, etc). Then you should know if you can live with some noise or clipped highlights. A general rule could be to expose to the most important subject for your client, director or story-wise. For dark, moody, contrasty images, just try to feed your sensor with light, using more light (which also improves contrast, as the unlit parts of the frame will appear darker) or using larger apertures. Remember that while shooting RAW, but seeing a REC709 (redgamma 3, redgamma 4, etc) lut applied, it's just visualization. What looks a bit bright at 800 ISO, can be very moody at 320, and if nothing is clipped, will always give you cleaner images and can be very dark as well. If you light to 800 ISO and you already begin underexposed and not using your full light power, you can get easily into trouble. So, for the situation you initially described, don't use less light if you are already happy with your set-up, just lower the ISO so you, the director and everybody on set is confortable with the look in terms of brightness.

 

[Aaron Lochert]

I did boost the ISO a bit to see if that would help but the difference was minimal on the goal posts.

There's a fundamental misunderstanding here how ISO works in these cameras. That's okay; it's counter-intuitive.

The sensitivity of the sensor never changes in a RED. Remember that. ISO is basically a brightness adjustment after the fact, it's no different than leaving it dark and then boosting the image in the computer. The goal posts and stoplights represent what the sensor is seeing, therefore they're totally independent from ISO changes. If you adjust the ISO and nothing else, you won't clip any more highlights and you won't reduce any noise in the shadows.

So when everyone in here is telling you to use a lower ISO, basically what they're saying is to feed the sensor more light and then use the ISO adjustment to darken the screen so it doesn't look so bright. Adding/removing light via shutter angle, aperture, ND filters, and lighting is the only way to make a difference in the recorded image.

and didn't really want to add more light on her or the background.

Lighting is all about ratios. What makes something look "moody" is that the subject is lit in a certain way relative to the background. So if you liked how it looked at ISO 800, you can get that same look at 400, provided you can either open up one stop or add one stop of light to the entire scene, not just the subject or background. This ensures your ratios are still intact. If you add more light to just the subject, the background will be darker in comparison. If you add more light to the background, the subject won't stand out as much. This is the entire bread and butter of a DP's work: ratios.

 

[Noah S]

Thanks Ignacio and Aaron! Very good lessons and explanations. I think i have been too married to "I need to keep the ISO at 800 as much as I can because that's what the sensor likes.".

 

[Linda Barzini]

The sensitivity of the sensor never changes in a RED. Remember that. ISO is basically a brightness adjustment after the fact, it's no different than leaving it dark and then boosting the image in the computer. The goal posts and stoplights represent what the sensor is seeing, therefore they're totally independent from ISO changes. If you adjust the ISO and nothing else, you won't clip any more highlights and you won't reduce any noise in the shadows.

So when everyone in here is telling you to use a lower ISO, basically what they're saying is to feed the sensor more light and then use the ISO adjustment to darken the screen so it doesn't look so bright. Adding/removing light via shutter angle, aperture, ND filters, and lighting is the only way to make a difference in the recorded image.
.

+1 This.

 

[Mohammed Almedfa]

From shooting a good portion of a feature film on Scarlet-X covering studio shoots & on-location day/night interiors & exteriors and quite a lot of greenscreen shooting. I tend to rate the sensor at 500ISO (I would bump the ISO up to 640 or so for a day exterior). If one is providing adequate lighting on skin & the various parts of the image for the intended finished look, I find 500ISO to be ideal. Since with sufficient lighting, you can push to 800ISO with a still clean image and are still avoiding over-exposure.

But in general I've gotten very clean results with good dynamic range by treating the sensor as a 500ISO sensor

And of course, being .R3D, it's critical to know that the ISO you set while shooting has no meaning beyond helping you get the right exposure as far as your aperture/ND/light level etc.