Clive Brincat Posted May 5, 2022 Share Posted May 5, 2022 Hey all (delete if this post is not relevant for this group) I've just got a sekonic C800 delivered few days ago. Today I had the chance to check this device out with some initial basic tests. (Check image below) - I've took a reading (bottom image) and balanced the camera to match what was measured on the sekonic (5440-5460) I've had just 1 daylight COB light on). Following this, I've put the camera on Auto WB which gave me a completely different result - camera rated this shot at 4900k. What baffled me was when i checked scopes on Resolve, it turned out the Auto WB was spot-on accurate and the sekonic was way way off. I am obviously missing something here. Does anyone have an obvious easy answer to this? Link to comment Share on other sites More sharing options...
Premium Member David Mullen ASC Posted May 5, 2022 Premium Member Share Posted May 5, 2022 Your lens isn’t neutral? Link to comment Share on other sites More sharing options...
Nicolas POISSON Posted May 5, 2022 Share Posted May 5, 2022 (edited) Maybe: the Sekonic is measuring the colour temperature of light coming from all directions, including reflections on side objects that are not neutral gray. The camera's meter is more like a "spot" meter, measuring only what is reflected form the scene to the camera. Edited May 5, 2022 by Nicolas POISSON Link to comment Share on other sites More sharing options...
Clive Brincat Posted May 5, 2022 Author Share Posted May 5, 2022 I think i might have "solved" the issue. I was pointing the C800 at the light source - this could be ok to determine kelvin of each light and matching different sources together. Once I placed and took reading of Temp from the camera side - i got a similar reading to what the camera was actually seeing (reflected light) Link to comment Share on other sites More sharing options...
Nicolas POISSON Posted May 5, 2022 Share Posted May 5, 2022 (edited) But the light going to the camera depends of the colour of the object that reflects the light. If a big red object is lit with a 5600K source, it will reflect red light to the camera. You would set the white balance to 5600K so that the object is of correct red. You would probably not want to raise the white balance up to 10.000K so that the big red object appears "neutral gray". Having the same coloured object in a great part of the frame is the typical situation where automatic white balance can be completely off. Measuring the light that hits the scene, as you did initially, seems the right way to me. The mystery remains unsolved. I was thinking of coloured specular light that could reach the Sekonic but not the camera. But this would be a bit strange since I would expect manly diffuse reflection. in your scene. Edited May 5, 2022 by Nicolas POISSON Link to comment Share on other sites More sharing options...
Nicolas POISSON Posted May 5, 2022 Share Posted May 5, 2022 Oops, I mistook the direction of correction for the big red object, but you get the idea. Link to comment Share on other sites More sharing options...
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