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  1. I'm trying to get a good setup for an interview with a subject talking to camera.

    I have three softboxes with halogen bulbs in them. When nobody is in the scene, the lighting is consistent, no flickering or flashing.

    When there's somebody sat there talking and moving their head, the lighting keeps changing based on their movement.

    I'm shooting at 25fps, the bulbs are 92w.

    I have the exposure set to manual so I can't think what it could be. I don't have Magic Lantern, could that be useful with this?

    Here's some example footage, this was shot at night: [video taken down now]

    If you scrub through the video, you can see it gets brighter and darker at points.

    I tried to test it just now in the daytime and it came out fine, it seems to be quite hit and miss.
    Last edited by SamBaker4; 15th Aug 2016 at 21:56.
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  2. aBigMeanie aedipuss's Avatar
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    the lights don't look like they are positioned correctly and it's overexposed on the subject's face in the beginning.
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  3. The subject wasn't in the right place though, the positioning I'm going to change etc, but any position I've had them in has had the fluctuation.
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  4. aBigMeanie aedipuss's Avatar
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    i didn't see much but the changes on the face from too much light as he moved around.

    maybe check to see if the camera has auto white balance turn on.
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    "a lot of people are better dead" - prisoner KSC2-303
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  5. The background is changing because of shadows being cast by the speaker. The top left, where there are no shadows, isn't changing. If you don't want the background changing you need to position the lights so that they don't cast shadows on the background, and use a separate light behind, above, or to the side of the speaker for the background.

    That's about the noisiest camera I've ever seen.
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  6. That would be because there's only those 3 lights and they're not positioned well because of lack of space :P

    But thanks, I'll arrange them better for the shoot.

    I'm not sure the lights will be strong enough that I'll be able to block out the windows in the place I'm filming in (an office)... but I don't want to use the natural light from outside because it's likely to vary a lot.
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  7. But if you look around 20-23 seconds, when the speaker is sitting, he's not moving much, but the shadows are too large and moving to be caused by him alone. It's almost as if someone is moving the lighting (flip back & forth between the screenshots)

    Here are some screencaps resized

    EDIT: pics removed at request

    Even if "auto" something was turned on in the camera, there isn't enough changing in the scene to elicit that type of response
    Last edited by poisondeathray; 15th Aug 2016 at 21:58.
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  8. I didn't look much at the second section. I see the issue now. Partly cloudy day?
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  9. That's a good comparison. It was shot at night, pitch black outside, and it was just him in the room.
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    The brightest and darkest areas don't shift, only the midtones, so that rules out the lights. My guess is that there is something going on with the AVC encoding which is shifting gamma depending on the contents of the frame.
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  11. If exposure is set to manual, make sure gain is as well. You may also be seeing the effects of diffused reflection on the lens surface itself.
    Last edited by smrpix; 15th Aug 2016 at 12:22.
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  12. That's a good point, smrpix. Make sure you are in full manual mode, not exposure priority mode. In the latter the camera will still auto adjust the other settings based on picture content.
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  13. aBigMeanie aedipuss's Avatar
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    even in full manual mode some canon dslrs have other settings that can effect lighting. white balance is one it's default is AWB -auto white balance. and there is an "auto lighting optimizer" menu setting that should be set to off instead of standard.
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  14. That was it, I turned the Auto Lighting Optimiser off and it seems to be fine now, thanks. Seems obvious now!
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