Banding lines at 50fps & 1/100 shutter speed?

[trapdoorfilms]

Hi All,

I hope I'm in the right place.

 

I am filming at a hotel which has some fairly dim yellow lighting, not a problem in itself, but there is this area where there are windows allowing more natural light to enter......great more light......BUT at this area banding appears!? I checked my shutter speed and fps and which was 50fps 1/100 shutter. f/stop 2.8 but stopping down didn't alter anything. I dropped my shutter as low as I could manually to 60fps which did help but didn't get rid of the lines.

What could be causing this? The hotel lighting was the same all over, just the windows allowing more natural light was different at this point. When I walked away from this area to a dimmer area in the hotel the lines went away. I'm confused as there doesn't seem anywhere else to go with the DSLR to deal with this? 

Any advice anyone?

 

Thanks very much

Martin