CWB question

[superdiver]

I understand how to use the CWB function.

The question I have is why white, grey and black cards and when to use which?

[tim]

Like with many things in photography, try it and see what works best for you :)

[superdiver]

But why would you use a grey or black card for a cWb? What is white about grey or black?

[tim]

White or grey should be fine. I think the Canon manuals say white card. Black's not useful. Grey is more usually used for exposure metering than white bal.

[superdiver]

How does one "exposure meter" and when?

[tim]

Put the 18% grey card under the light your subject will be under, set FEC/EC to zero, and meter. Transfer those images to manual on the camera. It's not really practical.

Some people use grey cards for white ballance.