I noticed that after I have upgraded the FW to 1.1.4, if I turn on Peripheral Illum. and use live view, there's a dark circle at the center of the screen. During an assignment on first night I have used on the new FW, the save image recorded the dark circle. But subsequently I keep testing it, it actually doesn't record the dark circle in the final image, be it RAW or JPG.
What does that dark circle spot actually do?