Fuji is famous for frequently releasing firmware updates and the constant improvement of its cameras. Now they just released the firmware 1.02 for the X100S here.
The phenomenon is fixed that the brightness of the OVF bright frame doesn’t change according to a surrounding brightness in case of ISO 1600 and higher.
Keep it up Fuji!… and what should be next? A fully customizable Q-menu as Ivar suggest in the comments? (RAW shooters would be very happy)
Patrick (and thanks for the link, Kim)
Fuji X100S update guide