What is better?

[ebann]

Q1: When shooting indoors in low-light (incandescent bulbs) with flash, e.g. weddings, is it preferable to maintain the ambient atmosphere, i.e. yellowish tint as our eyes see it, or have enough flash output (along with correct WB) to remove the yellow tint and have the natural colors shown?

When using flash, I mean enough to raise shadows, not to overpower ambient light. Mostly as fill-flash.

I've done a few tests shots (which I will post later) which exhibits the following:

The image with proper exposure (using gray card) for ambient light and using fill-flash with +0 FEC has a slight yellow tint. Doing the same shot with -1 FEC has more yellow tint. Underexposing the ambient light by 1-stop darkens the image a little and still has yellow tint. BUT using P mode, the yellow tint is gone exhibiting natural colors. AND using Av mode, the yellow tint is back.

Q2: How is P mode getting rid of the yellow tint? (note: all shot with AWB) I thought AWB would automatically remove the yellow tint.

Thanks!

[PhotosGuy]

is it preferable to maintain the ambient atmosphere, I wouldn't. And you'd better get the wedding dress the right color, too! I thought AWB would automatically remove the yellow tint. AWB isn't very good indoors. Notice that the very last exposure in the 2nd group of tests was of a gray card, & it's way off.
http://photography-on-the.net/forum/showthread.php?t=54281

I'd only use a Custom WB for something like a wedding, of the flash pre-set at the very least. How is P mode getting rid of the yellow tint? It's probably balancing for the flash, or maybe you just got lucky? ;)