Sunlight from the left was entering the hdmi slot of the camera during a 30 second exposure to cause the light spill on the right.
Once I covered over the slot with black tape the light leak disappeared, even during this 30 second exposure. (Yes, I always carry a small roll of black gaffers tape in my camera bag for emergencies.)
I first noticed this over the weekend and haven't been able to contact Fuji about the situation yet. Once I do, I will be posting whatever I find out.
UPDATE ON LIGHT LEAK 03/11/14: I contacted Fujifilm repair. They are definitely aware of the problem and do have a fix for it, which is the good news. The bad news is that the parts to make the necessary repair are not yet available, at least at the US repair facility where I called. I was told there is no definite arrival date for the parts, but expect it to be within a few weeks. Until then, black tape is your new best friend for solving the problem.
After I had a workaround solution to the problem, I proceeded with my project, which was to take a series of images similar to those below for later conversion to platinum prints.
|This time lapse image and the one below were taken with the 14mm Fuji lens on the X-T1 using a 12-stop neutral density filter to extend the exposure time to 30 seconds.|