Horizontal banding lines at 50fps & 1/100 shutter speed

[trapdoorfilms]

Hi,
I've come across something I don't know how to resolve.

I am filming in a hotel that has quite a yellow cast tranquil lighting throughout, not a problem. Then there is this area that has windows which let natural light in. It's a lighter area because of this, great...more light...BUT in this area I have suddenly got the banding lines?
I checked my shutter speed and fps, 50fps 1/100 shutter...i thought this should be ok. I dropped the shutter a slow as i can do manually, which was 1/60....this helped but doesn't eliminate the issue. When I moved back to another area that was actually dimmer....the lines go away. What's odd is that the artificial lighting was the same throughout the hotel...only when the natural window light came into play did this happen?
Has this got something to do with the mix of lighting....the artificial hotel lighting and natural light from the window? What is there left to do on a DSLR to tackle this issue? 

I'm using Canon 5D mkIII. Is there a setting on the camera to help with this. White balance didn't affect anything.

I didn't think this was an aperture issue as when I stopped down it didn't make any difference to the banding. Similarly, it had nothing to do with the volume of light as the darker area in the hotel was fine but this lighter area caused the issue???

Any help would be appreciated as we are shooting a wedding in 2 weeks and iv'e not come across this before.

Thanks

Martin

[Sebv]

did you try shooting at 30 or 24 fps with 50 shutter speed ? maybe it would have solved your problem

what was that natural light coming thru the window , street lights in night time ?

[trapdoorfilms]

Hi Sebv,

Thanks for your reply.

That's interesting, no I didn't try that. I would have thought shooting at an incompatible frame rate here in UK would have made it worse? Also, I'm not sure how to deal with that frame rate in post production as I would need the finished product in 25fps.

The natural light was daylight, no street lights on at the time.

The banding is horizontal and scrolls down the screen at a fair speed and looks like dark grey shadow lines.

 

Thanks

Martin

[Sebv]

If in pal you could have shot it at 25 fps with a shutter speed of 50 would have been fine

or shoot at 50 fps with a shutter speed of 100 or more but with all the light inside closed using natural lighting from the windows and boosting your exposure

 

no prob

[trapdoorfilms]

Hi Sebv,

As I mentioned in my post ...I was shooting at 50fps with shutter of 1/100. The matching of fps and shutter speed is not my dilemma.

I think you're misunderstanding that I was not struggling to get sufficient light, as the banding began to appear as I was nearer to the area where there was more light from the windows.

 

Thanks

Martin

 

 

[Sebv]

what i am saying is you should have synched your shutter speed (50) with the frequency of the lights inside

or close the lights inside and do what ever shutter speed you want