Nicolas POISSON

Hard to tell since this is quite blurry and heavily post-processed. This could be a huge collection of "Astera" type tube light, with and additional centre light which could be anything. Or maybe this is purely CGI ?

Just in case: the FX6 can shoot in S35 mode, but the resolution is then limited to 2K (same on the A7s3).

To me, it looks like there is: - a very soft key at 45° Horizontal / 45° Vertical (it could be 30°) on the left, kind of "Rembrandt" style. - a very, very, very soft fill (or a wide reflector) symmetric to the key on the right, to lower the contrast ratio. - strong overhead backlight, but not that soft: the top of the hair gets much more light than the side. It is far enough behind to not light the forehead, - another subtle backlight at the head level on the right, slightly behind the subject, again not that soft. It outlines the bottom of the cheek and the bun. - loads of make-up!

Just to make things clear: lossless compression used to be considered CPU hungry in the early 80's. But it is a very simple algorithm compared to the lossy compression of even mpeg-1. Every single lossy compression format performs an additional last step of lossless compression: jpeg, mp3, MPEGs of all kinds... The additional CPU cost is negligible, and if this lossless compression does not improve the ratio by much, it cannot hurt. (Some very old lossless compression algorithms were so bad that they could indeed increase file size, but this was another era.) When lossless compression has been performed once, there is little to no benefit performing it again on the compressed data. This is why "zipping" mpeg or jpeg files is not worth it. Lossless compression is useful for files that have no compression at all, which is common for text files, but rarely the case of media files.

I have hundreds of stills now, there is no best ones. However, I can share a few that are related to this topic. These pictures are taken from internet, so may not be representative of the movie. I have no clue of the processing done. Some pictures could have been shot by a set photographer with his Nikon Z6. First, two versions of the same still from the TV series Loki (2021, Dir : Kate Herron, DP : Autumn Durald Arkapaw). The upper one is the original, the lower one is a simulated extremely poor display with a gamma of 3 instead of sRGB standard 2.2. All shadow details are lost. Yet, you still recognize the characters, thanks to the lighting that outlines the contours. Now two pictures from live shows of a Flavia Coelho. In the upper one, there is almost no light separation. Her hair fades with the background, the pictures looks two dimensional. In the lower picture, you can see how back-lighting brings the talent forward. Shallow depth of field also helps. You could argue that for live performances, strong back-lighting is expected and nobody would complain it looks artificial. Well, look at the following grab from Patterson (2016, Dir : J. Jarmusch, DP : Frederick Elmes). Colours are very even, and separation of the woman’s hair is obtained through strong back-lighting again. I do not think it looks artificial : we assume there is some wall lighting right above the frame and on the right as well. Another grab from Patterson : here the girl’s hair is also separated from the background with drop light. It does not look artificial : we do expect light coming from the sky. It is very subtle, but it is essential. A still from Motherless Brooklyn (2019, Dir : Edward Norton, DP : Dick Pope). Here the woman’s hair does not receive any back-light. However, the background is extremely even, a bit blurred with shallow depth of field, and contrast in luma and colour between hair and background is strong enough so that separation is clear. So YES, you do not ALWAYS need to outline edges using lighting. And finally, a perfect example of chiaroscuro in a grab from the same movie. Look at the hat : - the rear is outlined through lighting over a dark background - the top and upper front are darker and not outlined, but the background is reflecting a lot of light. This is similar to lighting the background of a talent instead of back-lighting the talent itself. - the lower front is outlined through lighting, over a darker background. Same technique as the rear. Grab some still of movies you like, and analyse them. You will find that outlining edges with lighting is still extremely common.

I do not think that this is a question of "need" nor of "fashion", but rather of intent. You may add edge light, or drop light, or back-light to separate a subject from the background. You may light the background instead. You can motivate these lights with practicals if you want to sell it more efficiently. You can do this in a very subtle way, or a more apparent manner if you wish it to be more theatrical. You can add no back/drop/edge light at all, and work with depth of field and colour instead. And sure, you can even wish that the subject does not pop out off the background. I have build a collection of still grabs from reputable movies (blockbusters as well as indie films from all over the world). The strong "kicker" may no longer be fashionable, but using a subtle separation through lighting is still extremely common. It seems separation is often done through drop light, which is what you would expect in the real world with ceiling lights. There is something to keep in mind, though: when an image is displayed in poor conditions (uncalibrated display, strong ambient light...), you loose a lot of details in the shadows. But as long as the contours are there, you can follow what's going on. Separation using lighting helps a lot in keeping the image readable.

When using lossless compression, a 1:2.5 ratio sounds really, really optimistic. Sure it depends on the content, but for media I'd expect the ratio to be near 1:1 (no compression), since most media files include lossless compression as a final step anyway. You do not gain more than a few % when performing lossless compression twice.

I am not in the pro game enough to claim how it should be done. However, transmitting information about exposure, white balance, intended mood... from the DP to the colorist seems definitely a question nowadays. There is no unique answer. If ISO tells about the exposure, the colorist has enough piece of information. Say you have shot at ISO 200 and the sensor native ISO is 800, the colorist knows he/she should lower the exposure by 2 stops in post. The grading software may even do it automatically. But if ISO does not represent the exposure, which happens typically when using compensated LUTs on an external monitor, then the colorist cannot know. This is where you should agree with the colorist on how you communicate.

You can do almost what you want in post. Using the 'lift' tool would crush the blacks. Using the 'gain' tool would lower everything proportionally, keeping some details in the shadows. The 'gamma' gives you more latitude. These are the most basic tools. A colorist could use more advanced techniques. Any correction that goes toward reduction (lower exposure or smaller gamut, i.e. washed out colors) will always be easy, since you are lowering the noise (analogue domain) or getting quantization steps closer (digital). When increasing exposure in post, or pushing colors, there is a risk to get noise, or artifacts from quantization, camera built-in noise reduction, and compression.

You could also look at the Godox F200. Godox designs mainly low end stuff (like Amaran or Nanlite), but the Knowled series is targeted a bit more "pro" (better built, complete package including case, DMX control, V-mount batteries option...) https://www.newsshooter.com/2023/08/06/godox-knowled-f200bi-flexible-led-mat-review/ According to Matt's measurements, even with the diffusion, the F200 delivers twice the output of a 4x4 Kinoflo. You can fit two kits in a single case (that will weigh 40lbs).

I cannot answer directly. But my understanding is that a reflector beeing neutral or not mainly refers to white light or wide spectrum sources. For a saturated color with limited spectrum, a non neutral reflector would juste change the amount of light reflected, not its spectrum. So if you plan to use colorful gels, I guess it will not be much affected by slight inaccuracy of the reflector.

If you are monitoring the log signal, this is the expected behaviour in Cine EI mode. Apply any LUT and you will see the changes.

This is just the good old principle of exposure compensated LUTs on an external monitor. I guess most people here are familiar with it: create “Log to Rec709” LUTs that darken or lighten the image by 1 stop increment, send them to the monitor, and use them as an EI scale instead of the DSLR analogue ISO (which you leave at the base value). The point here is to create LUTs using maths and DaVinci Resolve. There may be simpler ways to do this with CSTs, but this is a topic I know nothing about. And part of the fun was to do it myself as a pedagogic exercise. What I tried before: 1- shoot a scene with a middle grey card in it. Set the exposure according to the manufacturer advice and keeping ISO at its base value. Then shoot 1 and 2 stops overexposed, 1 and 2 stops underexposed. I guess the best is to change shutter speed (same depth of field), but aperture does the trick. Import all the stuff in DVR. Add the “Log to Rec709” LUT as the last node. Then add a second node before, and adjust offset with SDR wheels, or global exposure with HDR wheels, so that middle grey goes back to the reference. HDR tools work better, but both are far from perfect. 2- same as before, but fine-tune using whatever colour-correction tools you want (especially contrast, saturation, and the curve tool), so that compensated images visually match the normally exposed one. This is a trial-and-error method that leads to better results. But not very scientific. After that, sandwich the colour correction node together with the “log to rec709” in a single LUT (one for each compensated exposure), send them to the monitor, and use them instead of the DSLR analogue ISO. You get Sony’s “Cine EI” feature on any DSLR. This works well for mid-tones, and this may be enough on set. But this can be improved. LOG profiles are documented. Manufacturers give the formulas to switch from real world scene reflection to log coded values, and the other way around. Thus: - starting from a recorded log signal, we can find what was the reflection - compute what would have been the scene reflection if the sensor had been exposed 1 or 2 stops higher/lower - from that simulated exposures, find what would have been the log codes for these reflection. We can compute the curves that make a 1-2 stop over/underexposure look like if it was correctly exposed. I used Scilab to program this, but this can be done in any spreadsheet program. slog3.sci Here are the curves for SLog3: Note: these curves are log space to log space, and SLog3 does not go below code 95 (10bit scale). The curve shape below 95 does not matter. As the compensation curve will be drawn manually in Resolve, it helps to determine the points corresponding to the grid of the curve tool (25 intervals ranging from 0 to 100% Luma). Here it is for SLog3: A few more notes: - the curve tool in DVR uses splines, which do not allow for sharp edges. It may be better to have the lowest point at coordinates [0, 95] rather than [0, 0]. - upward compensation leads to values above 1023 (above 25th grid line). The best way to handle this is probably to draw manually some kind of highlight roll-off. - From what I tested, 5-8 points are enough to define the curve (example below for Fuji F-log) This gives a much better base than playing with offset or HDR exposure. This is still not perfect and I had to bring up lowlight saturation a bit for the negative compensation LUTs, and bring it down for positive compensation LUTs. But I could get good similarity across LUTs tweaking very few controls. Here are the results on Fuji F-log, starting from +2 stops compensation (underexposed sensor) to -2 stops (overexposed sensor). The 3rd image is the reference, exposed normally. +2 stops (sensor underexposed by 2 stops) +1 stop Standard exposure: -1 stop -2 stops The curtains lost all details in the 2 stops underexposed shot. Even with “only” one stop underexposure, there are quantization problems near the gray card, where the magenta turns into brown. My understanding is that my camera’s Dynamic Range (Fuji X-T30) is centred at +/-5,5 stops around middle gray at standard exposure. Underexposing the sensor by one stop leads to only 4,5 stops below, which I expect to be too low for many situations. Highlights do clip in the 2 stops overexposed shot, visible in the specular reflection on the tiny aluminium PAR spot. However this scene does not contain much highlights, thus it does not appear that terrible to me. Following other tests I made, the most common exposure I would use is overexposing the sensor by 1 stop, which sets the DR at +4,5 / -6,5 stops around middle grey. Comparing to other manufacturers, this asymmetry toward low light seems common. Depending on the scene, overexposing by 2 stops might even be acceptable. Thus, I could think it as “the nominal exposure could be 1 stop above what Fuji says”. Final reminder: write it down somewhere and tell the colorist. The meta-data claims ISO 640 whatever the LUT.

When bypassing the capacitor, both the noise floor and the clip threshold are lowered. This does not change the dynamic range: the ratio remains the same. It is like saying 1000 to 10 has the same ratio as 100 to one. What you gain in noise is what you loose in highlights. The lower base ISO does not get obsolete as: - the whole DR is unchanged - base ISO of 800 is more convenient for well lit scenes, which are probably more common than low light scenes. For instance, you are shooting outdoors during a sunny day. Using base ISO 800 and EI 800, you set-up your aperture so that 6 stops above middle gray and 10 stops below fit your needs. If you were to switch to base ISO 3200 EI 800, you would have the same exposure, but now only 4 stops above middle gray. Your highlights are clipped. To avoid that, you either need to close your aperture by 2 stops, or put 2 stops of NDs on your lens. At the end, you get the exact same noise and clipping relatively to your scene... but you need ND filters. When switching from a lower to a higher base ISO keeping EI the same, you cannot apply the usual rule that higher ISO (indeed, higher EI) protects your highlights. This is the exact contrary. It does not help that "ISO" is often used instead of "EI", which made no confusion until dual base ISO was invented.

If you want to calculate intermediate 1/3rd stops values of aperture, you have to cumulate the cube root of 2 (1/3rd stops) and the square root (radius vs. surface). This time, the basic maths are: (X^a)^b = X^(a*b) The multiplier becomes : sqrt(2^(1/3)) = ( 2^(1/3) ) ^ (1/2) = 2^(1/3 * 1/2) = 2^(1/6) = 1.122 For example, starting from f/2 f/2 f/2+1/3 = f/2.2 f/2+2/3 = f/2.5 f/2.8 f/2.8+1/3 = f/3.2 f/2.8+2/3 = f/3.6 f/4 ...