I encountered Katherine during the LG TV promotion in one weekend.
The venue was dark and the background light of the shop created a rather serious backlight situation.
As I did not want to distract Katherine using my flash, I had to make use of the weak light emitting from the LCD TV in front of her to fill in the contrast.
In this situation, wide open aperture and high ISO is again the only option.

The photo is shot in RAW and converted from DPP. Final image is obtained by further processing using PS CS and NeatImage