Attenuation of light

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  • #198716

      Hello Roger,

      We tend to place actor close to the window to get proper exposure. However, it would become more tricky if we are dealing a wide shot with one actor standing by the window and the other one is at a distance from window. You will see different exposure level of the two.

      I tired to put source from above for enough ambient light. However, it feels unnatural like there is a source coming down. Sometimes it gets more tricky as the window is too small to get enough exposure from outside.

      In this case, How did you work out lighting attenuation in this large interior scene?




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    • #199365
      Max A.

        Hello Jeff, I’m not Roger Deakins of course (not even if I worked as hard as possible could I reach 10% of his level), but If I can join in your topic, I think most is about what you want to achieve and what you are looking for.
        Before starting to talk about the technical aspect (and I’m curious to read answers from Mr. Deakins, Mr. Mullen, and other experts dp’s here) I think is a matter of “look” and “taste”.

        For instance, I love “naturalism” so when I’m on a location scout, I tend to see how the location will impact in a natural way with my lighting, so if a room has only a small window and the story “call” for a “high -key” day interior scenario, my consideration with the director is that maybe that room could not fit for which we are searching for the story.

        In the technical aspect, I think you have to consider some aspects: First of all, how the window is located in the location, do you have the ability to control that window/s? Will you light that window artificially or do you rely on natural daylight? There is direct sun or bouncing daylight coming from the building in front of you, or the window is facing North and you will have “only” soft daylight coming? The angle of your Frame, do you shoot square and in front of the window? If so, do you need to be connected to the outside landscape or you will “blow out” your window?

        For example, a solution, if you could have control of the light outside, and maybe you don’t have to shoot straight to the window is to rely on the inverse square law for the fall-off of the light and then place your lamp/s at least 3/5mt. away from the window (but then you have to figure out if you will diffuse the light and how much you diffuse it to “recalculate” the fall-off), so that the difference in the lighting of your subject near the window and the other at a distance (but depends on the distance) will be not so extreme.

        In “the past” I often struggle with this kind of scenario and as you said bouncing light from the ceiling sometimes helped me but “destroy” the “natural” feeling and made me frustrated, in the last years I’m more serene, and I gladly accept the naturalness of things so that if a man is distant from a window and this is the only light source in the room, this man will obviously be less bright than the one near the window.

        This is only my thought, and I will follow with pleasure other answers for this topic.

        I wish you a peaceful day, and I apologize for my not perfect English.



          Hello Max,

          I am appreciated your informative answer. You are jumping out of box, which I never thought like that. I find it really helpful. Thank you so much.


            Your balancing values, if you want to calculate how larger sources fall-off see here.

            Gabriel Devereux | SOFT-LIGHT CALCULATOR

            If it’s a small source 4pi distance ** 2 is about right.
            Your sensor can resolve a linear range of light.

            Gabriel Devereux - Engineer


              Recreating the natural fall-off of skylight in a set with windows is very difficult due to the inverse square law. On the other hand, plenty of movies and TV shows have lit convincing day interiors even if the fall-off rate isn’t like it would be in real life.

              Obviously you start by working large and far as possible on stage to get a gentler fall-off rate for the soft light.

              In a wide shot that is static and the windows are to one side of the frame, ND grads or ND attenuators are useful. I just used an ND.6 attenuator a few months ago for a shot in a white kitchen where I wanted to light someone at a wall-mounted phone from the side but the wall was getting too hot even with flagging. A similar thing can be done in post with Power Windows as long as nothing is clipped but it’s nice to get it right in camera.

              For closer shots, you can sometimes use nets or an additional diffusion frame on the foreground person by the window to darken them relative to the background person who is deeper in the room. But of course once you go in closer, it’s easier to balance things.

              Yes, if the fall-off is too steep opposite the windows, you sometimes do things like bringing up the room with a soft ceiling or floor bounce. The softer it is, the less “source-y” it is.


                You can use the CTRL Light bridge reflectors to double the distance of a light that is close to your set which will help even the fall off in the room.

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