Roger Dowling

After a recent green screen shoot on Red at 4K of live action to be compiled with computor animation for a TVC.
I am wondering what the natural colour balance for the Red is.
I known you are able to select either daylight or tungsten, but does the sensor have a preference, or is there better performance shooting daylight as against tungsten.
I lit the shoot with tungsten as daylight lamps were not available.
Follow up from the animators is that there was a small amount of noise in the dark shadow areas.
I shot with the camera set on tungsten.
Any thoughts would be appreciated, Thanks.

Brian Drysdale

The RED sensor is at its best in daylight. There has been discussion in various forums about noise being an issue shooting tungsten and RED appear to have been working on a solution.

You could always use CTB on your lights.

Roger Dowling

I had thought that the Red was better in daylight, and with the raw files it really isn't such a problem to colour correct.
I didn't use CTB gels, as the screen area was quite large and use do lose some output in level.
Thanks for your comments.
Roger D.

Jon Fordham

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Charles Papert

I have also been told that, yes. We can only hope that the next generation sensor out of RED is tungsten balanced and at least as sensitive if not more so.

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Daniel Browning

That's good advice for beginners and fast shooting. Kind of like "f/8 and be there". But after you become more experienced with digital cinematography you can learn to use ETTR to reduce noise and boost dynamic range beyond what's possible when sticking to 320 (i.e. when you need less highlight headroom than 320 provides). Furthermore, in controlled lighting situations (sunlight, studio) you may learn to use filters (e.g. CC30M in daylight and 80A in tungsten) to make sure that each color channel in the raw histogram buts up to the very edge.

Charles Papert

So when using an 80a (which would knock the ASA down to around 125), are you saying that you are able to boost it back up again without penalty of noise etc.?

It couldn't really be more counter-intuitive to have to use a CC filter to shoot tungsten (usually the domain of interiors and night exteriors, exactly where you need the sensitivity).

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Daniel Browning

Without the filter, the blue channel will be way behind red and green, making it impossible to use the full dynamic range of the sensor. If blue is ETTR, then red will clip. If red is ETTR, blue will be far behind, with less signal and more noise. By adding filters, you can bring the RGB values closer together and ETTR for all three, making the most of the sensor capability.

As I said, it's only useful in controlled lighting. There is a lot of tungsten studio lighting. You could gel the lights, too, there are a lot of ways to bring the RGB closer together.

Charles Papert

Daniel, unless I'm reading you incorrectly I don't think you are really addressing my question.

I understand why you would use an 80a to bring the RGB values close together, that's a given. I'm asking you to clarify your statement about boosting dynamic range and reducing noise, in conjunction with the suggestion to use a filter that significantly drops the sensitivity of the camera.

Having to work in daylight balance for studio interiors or night exteriors is not a compromise I would be happy making. I prefer the control of small tungsten units vs small daylight balanced units and I don't want to have to double the wattage of everything and deal with CTB on tungsten units, again that's counter-productive. And to CC at the camera and more than double the wattage of my straight tungsten units--this is moving us back 25 years techologically, before the advent of high-speed negative. The paradigm for both film and video for years has been to add the 85 filter for daylight work where you can easily afford the stop loss.

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Perrone Ford

One could argue that filming with tungsten lighting at all is moving back 25 years.

With the movement toward HMI, LED, and Fluorescent, it's ALL moving to 5600k. 3200k lighting is fading quickly. Having to fight daylight in every outdoor scene or every indoor scene with a window makes far less sense to me than having a camera that works well in todays primary light temperature.

I also don't see the large difference between shooting on film with Tungsten balanced film (like 5218) and filtering the camera which is done on nearly every shoot I can think of, is any less a problem than shooting daylight balanced video and having to filter for 3200k lighting on the camera.

I'd bet good money that if Kodak introduces a new Vision3 stock that is daylight balanced and works like 5218, many cinematographers would jump at it.

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Charles Papert

Not on the vast majority of sets I work on. LED's and fluorescent come in 3200 and 5600 flavors. HMI's are great for their punch in daylight settings but are generally more troublesome than their tungsten counterparts (hot strike issues, color temp inconsistencies, flicker etc).

No-one fights daylight for exteriors, you just shoot daylight or tungsten with an 85 as I said. I am struggling to recall ever seeing a completely controlled setting (i.e. on stage) lit for 5600 unless there was a reason for it.

Not sure what kind of filtering of '18 you are referring to; for tungsten interiors/night exteriors no CC is required and the full sensitivity of the 500 ASA means less power requirements, heat etc. The same environment with a daylight balanced sensor and CC on the lens will mean significantly more light required to get the job done. Any practicals in the scene will have to gelled or have their bulbs replaced with 5600 equivalents, if even available (not possible with halogens). Daylight scenes are just more likely to be shot at higher light levels, that's the nature of the beast--that's why it can afford to be filtered down.

Doubtful, or they would have done that already. Kodak is working fast and furiously to put new products in front of the cinematographer based on their needs; 18 wasn't even around all that long before 19 came around.

I'm not some tungsten stalwart, by the way. I shoot plenty of daylight balanced stuff, very familiar with the options that are out there. Obviously when shooting on location with windows and doors that open to the outside, one has no choice in the matter. It's just that when I need a quick bounce, highlight, fill a dark corner or sparkle the eyes I find it easier to work with tweenies, Dedos, peanut lights, practical globes etc. than most of what is available in the 5600k realm.

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Perrone Ford

I will grant you that working with the ballasts and so forth to shoot HMI is more troublesome (and costly). But I haven't heard of temp inconsistency and flicker on modern quality units.

Is this because everyone already owns a ton of 3200k fixtures already, or is it because 3200 is inherently better? I know for video, the added blue information in daylight balanced lighting makes for much cleaner video. Especially at lower light levels. Obviously with film, this is not a concern.


I am talking about a great many cinematographers that I read about shooting '18 outdoors. It seems to be the most popular Kodak stock over the last few years and is used indoors as well as outdoors. I have also heard very few people rate it at 500ASA.

Maybe so. It seems that cinematographers tend to move to 100D of even 50D outdoors.

You are certainly correct here. I prefer to shoot daylight balanced because my cameras look better with it. Were that not the case, I'd certainly not do it.

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Charles Papert

HMI bulbs can definitely run off-temp (they change as they age) and sometimes need correction. Tungsten can do the same but usually not enough to require gelling. Flicker is not an inherent issue with electronic ballasts but it is common to have heads start to flicker (issues with lamp, head or ballast). They are useful instruments but honestly not the most stable.

.

A couple of things I didn't mention before; it can be a lot easier to augment existing lighting in an interior rather than swap everything out. Also tungsten units can be dimmed, either with hand squeezers or a dimmer board. They are cheap, plentiful and workhorses.




Right, gotcha. Well, to re-iterate what I was saying before--daylight exteriors have plenty of light, so it's easy enough to add a high level of 85ND as needed. For night and interior work, high speed is the key and it is brutal to lose it to filtration. I myself rate the 18 at 400 for a denser negative but if necessary you can rate it much higher and of course push it. I actually shot with it at magic hour last week and due to time and physical constraints, had to forego adding an LLD and just shot it straight with a 5600K cast. It came out perfectly in telecine, although obviously it is not ideal to have to do so (something along the lines of the original point that Daniel made, which is that it is less than ideal to have to pump up one of the channels).

Anyway, the main point I was trying to make is that I would much rather shoot night and interiors with a high speed tungsten setup than a lower speed daylight-corrected-to-tungsten setup if I possibly could.

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Daniel Browning

Let me clarify something: I did not mean to imply that Jon was a beginner, only that the advice from the RED tech was good for beginners. Now that I think about it, I was wrong to say that because it's much more than that and has negative connotations besides. I apologize.

The point that I should have made is that 5600/320 is a good starting point, but there are circumstances when one can deviate from it to get more dynamic range and less noise.

When one needs more highlight headroom than 320 provides (from middle grey in standard gamma), the camera should be rated at a higher ASA, as frequently mentioned by RED. Then in post the middle gray can be moved back up to the place it was at 320 and the highlights can be preserved in the tone curve.

But when one needs less highlight headroom than 320 provides, especially in just one or two color channels, the camera can be rated at a lower ASA and/or combined with filters for lower noise and higher dynamic range.

Daniel Browning

Imagine a studio shoot with with tungsten lights. The RAW RGB histogram shows the red channel is -0.1 eV from the clipping point, green is -0.3 eV, and blue -2.1 eV. When the image is white balanced, blue channel becomes much noisier than the R/G channels. With the added noise, a decision is made to clip blacks at -8 eV and use a certain S curve to darken the shadows. Eight stops of dynamic range are used.

An 80a filter is added. Now the RAW RGB eV from clipping is: -2.1, -2.3, -2.1. The wattage is increased four-fold. RGB becomes -0.1, -0.3, -0.1. When the image is white balanced, the blue is now equally noisy as red and green. Using the same level of "taste" (tolerance for noise) as above, blacks would be clipped at -10 eV and a different curve may be used that leaves more detail in the shadows and perhaps even boosts them. Ten stops of dynamic range are used.

Here's another scenario: imagine that your exposure has blue at -0.1 eV, but green and red are overexposed by two stops (i.e. clipped highlights). Maybe they're just specular or unimportant, but an 80a filter would restore those highlights with no change in exposure or wattage.

If the image will never be white balanced to neutral because the warm look is desired, and the exposure does not contain clipped red highlights, then the filtration would pose no advantage. It would not harm, either, as the blue can always be subtracted in post.

Similarly, in many sunlit shots, the green channel can be a stop ahead of red and blue. A magenta filter brings them closer in line.

That's how bringing the RAW RGB values closer together gives you more dynamic range and reduces noise. In many circumstances, there will not be time or controlled lighting available to get the histograms lined up and butted up against the right perfectly. Many other times a half stop or two stops in dynamic range and noise are not important enough to be concerned about. But it pays to know techniques to do RGB ETTR for the times when it's possible and desirable.