Why is this happening to the screen in my picture?

[AimeeG]

Last night I took pictures at a large event with 3 huge screens on stage.  I noticed that each time I took a picture, the screens on stage changed colors.  I was shooting in Auto WB so changed to K but it still happened.  The WB doesn't seem to change, just the screen color.  And it was most definitely not changing colors.  Here's an example from Lr.  What causes this and is there any way to make it not do this?  I have to show all these images together so it's going to be really obvious.  

 

Thanks! ~Aimee

 

[Christina Keddie]

That's just the nature of getting a split second of a screen's light captured in a photo.  Try taking a photo of a TV and you'll see what I mean.  Screens work by emitting continuous light in waves, and the waves blend together way too quickly for the human eye to discern the color patterns, but taking a photo of it means you capture it mid-wave.

If you want to get highly technical to figure out how not to get this effect in photos, you'd have to know what kind of projector was being used, and find out the right sync speed to sync your shutter speed up to.  (You get a similar effect when shooting fluorescent light, with having to shoot with the right shutter speed to avoid off colors from the funkiness of the light waves.)

[AimeeG]

Thanks!  I figured it was something technical.  I'll talk with the tech guys for next time.  

[AimeeG]

Asked our tech guy at church and he said to avoid this I would have to have my ss below 60.  Not sure how that would look when hand holding and not using any flash.  But next time I see it happening, I'll try that and see.  

 

thanks again.