original:
#1
1/6 f3.5 ISO640
no flash
center-weighted
Incandescent
After WB adjustment in Lightroom using WB selector tools
#2
Temp:2200
Only Fired flash, and the original photo looks like:
#3
1/6 f4.2 ISO640
built-in iTTL-BL -1.0EV (Temp:2950, about 1m from subject)
center-weighted
Incandescent
The flash makes the color of the subject looks more natural or blueish while maintaining the yellowish ambient at the background.
#4
1/6 f4.2 ISO500
built-in iTTL-BL -1.3EV (about 2m from subject)
center-weighted
Incandescent
With the same aperture and shuttle speed, 1/6 f4.2, still can see the yellowish background. But subject is under-exposed due to -1.3EV of flash and too far from subject.
So, change the aperture and flash EV, we got:
#5
1/20 f4.2 ISO500
built-in iTTL-BL -0.3EV
center-weighted
Incandescent
The background is less yellowish and darker. While the subject turns blueish. This may due to stronger flash and faster shuttle speed. Hence has shorter time to capture the yellowish lighting but the blueish flash instead.
Observation
1. To see the yellowish ambient background, used shuttle speed less than 1/15.
2. The flash light becomes blueish under incandescent WB. So can properly use it together with shuttle speed to have a subject that is not so yellowish. Too strong flash or faster shuttle speed would turn the subject blueish.
3. To prevent yellowish subject under hotel lighting, use flash(under incandescent WB or other WB that has lower color temp) properly so that the subject less yellowish
