indoor video white balance setting

Discussion in 'Video' started by tom_dwyer, Aug 9, 2019.

  1. Hello All.....
    I'm shooting educational videos indoors. Where I live tends to have partly cloudy skies nearly always. As I shoot, the white balance setting appearance, when it's sunny, changes as clouds obscure the sun. Of course, it changes again when the sun comes back out. All the video tips I read before starting indicated not to use auto white balance. Is auto white balance the way to go or is there a technique that works better for this? I'm very comfortable behind my Nikon D7200 for still photography, but I'm most certainly a video neophyte. Thanks in advance for any help.

    Tom
     
  2. I'd recommend using this editor https://movavi.com/, it can edit and convert videos, has a lot of filters and supports a lot of file formats.

    Mod note - link was flawed, now fixed.
     
    Last edited by a moderator: Aug 12, 2019
  3. William Michael

    William Michael Moderator Staff Member

    I have the Movavi Video Editing and Post Production Suite and it is reasonably efficient and easy to use, but not a comprehensive professional suite - it is worth a try, but, personally I wouldn't go down that path.

    In any case my comments relate to any and all Post Production 'fixes' for White Balance variations - it's easier to not have to fix by attaining a Stable or as near to Stable White Balance, in the first instance.

    Note 'a Stable White Balance' does not necessarily mean 'the Correct Final White Balance' - it means "non-varying"

    I'd be looking at how much variation of shot angle and camera movement that you have for any one video session and from that base ensure that the interior lighting is always dominate over the diffused window light and that the interior light is always even in white balance across all the shooting areas.

    This may mean replacing the interior ceiling lights with new ones all from the same batch and the same age, or using in more video lights, depending upon how you are lighting the scene. Obscure as much of the window light, by closing the blinds etc.

    Then set a Manual White Balance and stick with it.

    An occasional variation of WB at the periphery, for example on shelves near the windows, will hardly be noticed if the main Subject(s) and the main shooting areas are in a Stable White Balance and especially less noticed, if there is a lot of dialogue.

    WW
     
    Last edited: Aug 12, 2019
    Ed_Ingold likes this.
  4. As with other things photographic, it is better to be consistent than correct. Most color balance can be corrected in post, but not if AWB is changing things. As William indicates, keep the subject in the same light and let the background float.

    I have bi-color LED panels for supplemental lighting. I use a Lumu meter, which plugs into a smart phone, to match their color temperature with room lighting.
     
  5. Automatic white balance is unreliable, because it is based on what the camera "sees," which seldom consists of neutral colors. I recently purchased an X-Rite "Passport" for video, which I use to establish a color balance reference in post. It seems pricey, but I think it's worth the money in time (and reputation) saved. It's small, protected inside a folding plastic case, and easily carried with other gear without risk of damage. The targets are specifically designed for video, whereas other "Passport" targets are better suited for still photography. The target is white, matte-finished and about 80% reflectance - well within the exposure range.

    When shooting, I use a fixed white balance close to the ambient conditions, typically 3200K, 4200K or 5500K. I open it and balance it on a stand or piece of furniture, and shoot a 10 second establishment clip. If that's not convenient, I hold it at an angle in front of the lens. It doesn't have to be focused to work. I'm working mostly in log gamma profiles, so you can't really tell much from eyeballing the monitor as you shoot.
     
  6. I have found that "warm" commercial lighting and stage lighting is a lot warmer than you might think. Using a Lumu dongle for my iPhone, I find the temperature is typically about 2600K, well below the 3200K expected from hot studio lights. My Sony FS5 has fixed color temperature settings when using S-Log gamma - 3200, 4200 and 5500. My Sony still/video cameras are more flexible, but setting 3200K on each requires only a little tweaking when grading/matching color in Premiere Pro (or DaVinci Resolve), and makes matching much easier (almost the same settings).
     
  7. Thanks everyone. I appreciate your info.
     
  8. I bought a couple of diffusing screens you can hold in front of the lens. I find they must be pointed directly toward the light source to be effective. Coloration in the subject and walls bias the reading. A white or grey card (or step chart) held in front of the lens at a 45 degree angle to capture the light seems to be the most reliable tool. If the subject is lighted differently than at the camera, I try to include a relatively white object, like a piece of paper, in the scene, or a white shirt, and do a screen grab. That usually requires some fudging in post to get skin tones correct.
     
  9. Not all indoor lighting is the same, nor outdoor lighting for that matter. White balance is basically a red/blue balance, plus luminance. In RGB color, there are only two degrees of freedom for color, plus luminance. For basic adjustments, Premiere Pro (Lumetri), DaVinci Resolve and Final Cut use an Orange/Blue balance for color temperature plus a Green/Magenta balance for fine tuning.

    All of this is contingent on light with a continuous spectrum based on black body radiation. In practice, that is an approximation at best, and at worst, useless. Fluorescent lighting and discrete LED lights tend to have three color components, which don't line up well with color film, digital sensors or your eyes. Two video cameras seldom have the same response to light, and must be individually balanced to match colors. Unfortunately these adjustments can depend strongly on the quality of light in a particular environment and the exposure level, and must be matched visually by the principle of metamerism.

    Controls for luminance are more detailed, with often obscure modes of action. Typically you have sliders for IRE 0, 30, 60 and 90. Alternately, you use luminance curves to establish the end points and bend it in the middle for tuning.

    A more detailed and scientific approach can be done using a standard color and reflectance chart, such as an X-Rite ColorChecker card. They're not cheap. The patches are made with pigment paint rather than a printing process, with predictable reflectance across the visible spectrum. The process is similar to that used to calibrate monitors, printers and scanners, but not nearly as automated. The link below shows how it works with Premiere Pro, and similar videos are available for DaVinci Resolve and Final Cut.

    The ColorChecker Video Workflow with Premiere Pro

    The authors of these videos describe the process as "foolproof" and "perfect," an exaggeration. They will get you near the ball park, but not necessarily in it. Ultimately you must tweak the results to suit your taste. That's a lot easier if you establish a baseline using these tools and others at your disposal.
     
    Last edited: Nov 14, 2019
  10. Exposure level has a significant affect on color balance. You become acutely aware of this problem when matching scenes or cameras. Make sure to check the exposure setting (in post) when the color sliders alone don't do the trick. Most of the time the nearest 1/2 stop is good enough, and 1/4 stop is the finest increment I use. I rough in with the slider, and fine-tune numerically.
     

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