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Technically you’d have a little less noise at 5600K because sensors are naturally close to daylight-balance – the blue channel has to be boosted after raw conversion to make the image balanced for 3200K.
However, regarding color reproduction, that is more an issue of the lighting technology involved rather than the color temperature. True daylight and tungsten are continuous spectrum sources whereas LEDs have spikes of color at different frequencies, some have more color phosphors / spikes with smaller gaps, creating more accurate color reproduction.
Yes, if you go from 100 foot-candles to 200 foot-candles, you’d have twice as much light so would have to close down by 1-stop to maintain the same exposure. Or cut the ISO by half. Or close the shutter angle by half.
I’ve never used contrast ratios because that requires some conversion math… but in terms of measuring and noting the shadow level, if that’s done, it’s more about matching coverage. You light the wider shot by eye and create the contrast you want, but sometimes when you start covering a scene, you might take notes on the shadow level versus the key for matching purposes, especially if you are shooting VFX elements for compositing.
Of course everything is on a spectrum, it’s not like the choice is between anamorphic lenses with zero anamorphic artifacts versus the funkiest, oldest, more flarey and distorted anamorphic lenses ever made. But it seems to me that one would want some anamorphic artifacts, even if subtle, if you were going to pick anamorphic — if all you want is a 2.40 frame, there are easier, simpler, cheaper ways of getting there.
The only reason I am “split” on the subject, as you say, is that if you reduce every optical indication that something was shot on anamorphic lenses, then why shoot on anamorphic lenses? In the pre-D.I. days of film prints, a 35mm anamorphic production used a larger negative area than Super-35 cropped for a 2.40 image plus every generation was contacted printed. And there was somewhat less depth of field on average compared to Super-35 due to the longer focal lengths used.
But now with digital and larger format cameras, none of those are issues; even with 4K cinema release, the current digital cinema cameras with spherical lenses deliver enough resolution, and shallow-focus isn’t hard to get with fast spherical lenses. So that leaves using anamorphic lenses for their unusual optical qualities.
The focal length you use also depends on how much of the plate you’ll be cropping into. With car scenes, usually there is a 1:1 ratio because the edges of the screen are mostly blocked by the car body, plus in the days of 35mm 1.85, your plate was probably shot and projected 4-perf 35mm full aperture but your camera’s 1.85 frame lines were slightly cropping in on this. So you’d use the same focal length for the plate and the stage shot. But if you need to crop into the projected image more, you should shoot the plate on a slightly wider focal length.
The thing with dynamic range is that you don’t always need a lot of it… until you do! You may be rolling on a second take when suddenly outside the window the sun comes out and hits a white car parked across the street.
It’s just the nature of additive versus subtractive color — if you want to make a primary color deeper and more saturated in a film print, it needs more dye so it gets denser, letting less light through. You want to make a primary color more more saturated with a digital projector you let more of the pure red, green, or blue light through. You can go even further with RGB lasers as a light source.
He looks lit by a softened HMI coming from the right through another window, but whether the window in the middle of the frame needed ND gel is hard to tell – it looks sort of misty/foggy and overcast out there so maybe no ND gel would be needed. In a location like this, you might have hard acrylic ND gel panels made for each window that can be quickly slapped up — or removed as it gets darker outside.
“Overlight the cafe and bring it down in post” is not how that works, what you are asking is if they lit the interior brightly enough to get closer to the exterior level so there was less of an exposure difference. At that point, they’d stop down the lens and/or use ND filters to expose the shot for the brightness they wanted, they wouldn’t need to bring it down in post. The truth is that if the background is very bright, you’d want to expose to retain some detail — leaving it very bright for post to then darken it back to normal risks having clipping (though this movie was shot in film, which has more latitude for overexposure.)
It’s an age-old question, how to retain details in a bright background through a window. Do you do it by bringing up the interior? Do you do it by adding ND gel to the windows? (You’d still need to add some interior light because if the room is mainly lit by window light and you darken all of them with ND gel, then the interior gets darker too, it’s just that because it’s darkened with ND gel, it takes less light level to bring up the interior, i.e. small LEDs rather than bigger HMIs.) Do you wait for a less bright time of day or weather condition rather than use ND gels?
Now if the actor is very close to the windows and thus receiving a lot of light from them, then the difference in brightness from exterior to interior might not be as bad you think, some white cards reflecting some of the sunlight back at the actor or minimal LED lighting might be enough to add some detail to the shadows.
If you shoot raw, then color temperature is usually just metadata. If you record log, then probably it would be best to shoot at whatever the color temperature of your primary light sources are for a somewhat neutral color image.
I would consider the tonal scale value of whatever colors you use for sets and costumes — it’s one reason why old b&w movies used to dress people in browns and grays, it was just easier to judge contrast by eye that way.
Over the century there has been all sorts of lighting styles for b&w, from the classic noir-ish era of the 1940s that most people think of, to the softer tones of 1930s films, and the more natural look of 1960s movies from Europe. I don’t think there is a right or wrong approach, it’s just that you want to think in terms of grayscale because sometimes a low-contrast image looks nice in color but too washed-out in b&w unless there are some tones in the subject that add contrast back in (for example, think of a foggy day with a man in a dark coat, which can look nice.) It can also be harder to direct the eye to the actors and separate them from the background which is why you want to think of tones and how that face is framed against the background. You don’t have to resort to backlighting, simply putting a dark edge of the subject against a highlight or vice-versa might be enough.
If you’re going for a cool look by pulling the 85 filter on tungsten film in daylight, then you aren’t really correcting back to neutral, you may be just correcting part of the blue out.
In terms of using daylight film in tungsten or mixed sources, that’s been done many times. Both “Emma” (1996 version) and “Backdraft” used 250D daylight film for interiors to make candleflames and fire look more orange, mixed with some daylight-balanced light. Robert Richardson used 250D daylight stock for a tungsten-lit night exterior in “Born on the 4th of July” for a warm look. In fact, 3-strip Technicolor was daylight-balanced from 1935 to 1952, and sometimes tungsten lamps were used for orange lighting effects (like firelight, etc.). But in all of these cases, the image was not corrected back from orange to neutral.
I have heard of scenes shot on daylight film in daylight corrected from neutral to cool though — for example, the WW2 flashbacks in the first “X-Men” movie was shot on 50D with a bleach-bypass process and then timed cool.
So unless a warm tone is desired by not correcting in post, I can’t imagine the reason for shooting 250D all under tungsten but correcting it back to neutral unless it was simply a stock emergency on location and no tungsten stock was available.
“a movie that goes through a D.I. that is intended for both digital projection and a DCP” — I meant a movie intended for both digital projection (DCP) and a film-out for print projection.
“Dunkirk” is a separate issue, it’s not a re-release of an old movie — in this case, as with most Nolan films (except “Tenet” for some reason, I think he had to use a D.I. to make the release date) he doesn’t go through a D.I. because he wants to be able to contact print the 15-perf 65mm IMAX footage and show that print in IMAX film theaters. This meant that the 5-perf 65mm footage in “Dunkirk” was optically blown-up to 15-perf 65mm so it could be cut into the IMAX negative. So if you see the 15-perf 70mm print of “Dunkirk” you are seeing it as Nolan intended. Yes, film prints have more contrast to them, giving them rich blacks but less shadow detail, which you can see happening in the film prints of “Oppenheimer”. To talk about color depth in this case is a bit misleading — a film print uses subtractive color (YCM) and a digital projector uses additive color (RGB) so a digital projector can increase saturation without decreasing brightness. But in terms of the color depth, a movie that goes through a D.I. that is intended for both digital projection and a DCP uses a Kodak Vision print emulation LUT in the D.I. session in order to not create colors outside the range that can be shown in a film-out that is printed on Vision print stock.
Now as for old digitally-restored movies, yes, you can wonder what the point of a film-out would be other than the fact that unless the digital theater has laser projection, a film print has better blacks and contrast. But laser projection is taking over so that soon won’t be an issue. If one was a purist, I could see making an effort to see film prints made from film masters, but to insist on seeing a film print of a film-out from a digital file seems a bit pointless. In general I prefer digital projection of film restorations done digitally; however I do like seeing prints of film masters, like new 70mm prints of old 65mm movies that haven’t been digitally restored, or archival 35mm Technicolor dye transfer prints, which I feel have their own unique look — the print itself is part of the experience, especially if the movie was shot in 3-strip Technicolor.
