20D WB shift help please

[pfogle]

Sorry if this is a dumb question... ;-)

On film I like to use an 85b warming filter.

On the 20D, the WB shift doesn't seem to work on custom WB. When I select custom WB with a shift of 0, I get the correct WB, but if I dial in a shift to amber, the base line WB isn't the custom WB, but something else, possibly AWB.

The manual isn't clear on this, but does anyone else have a similar experience, or can suggest how to get a warming effect on top of a custom WB?

any suggestions welcome!

[Tomasz Dziechciarz]

Hi,

Use this WB in mode K ....

If I understood you properly ...

[pfogle]

Hi Tomasz,
thanks for your reply.

that's what I thought, it works in mode K... which is fine, except it doesn't really solve the problem, which is I want to use a custom WB when I *don't* know the K, and *then* add the warming...

seems like I'll have to add the shift in PS.

Shame they didn't think this one through a bit better. Still, it's a great camera!

[Jon]

The idea behind CWB is that you're matching the sensor's (recording) to the light to achieve a pure, neutral white. Accordingly, no shifting should be necessary. If you want CWB with warming, use an 80A (complement to the 85B) to photograph your target. But that's a pretty strong correction. Most people would use the less intrusive 81-series for their warming.