Jump to content

White balance test


Recommended Posts

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?

1.png

2.jpg

Link to comment
Share on other sites

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 by Nicolas POISSON
Link to comment
Share on other sites

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

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 by Nicolas POISSON
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...