60 Hz like hum in Red Epic picture?

[John Moore]

On a multicam Red Epic shoot we have what looks sort of like 60Hz hum in multiple cameras. When we look at it in Rec Cine X, Resolve and Avid there is a hum like line horizontal that runs top to bottom at about the pace of a 60Hz hum. It's a relatively thin line that brightens the picture slightly and is noticable on the medium greyish back drop pillars on the stage. A floating ground was suggested as a possible cause by one colorist. Is it possible to have a floating ground actually effect a Red Epics Raw files. There were probably many potential sources for a ground loop with Pix recorders and remote feeds to the director monitors on this multicamera stage show shoot. I just don't see how a ground loop/floating ground would effect the Epic's internal path to the Raw file. Can a ground loop actually effect the sensor pick up? This was shot at 29.97P in the US. Another thought was perhaps there was some light source that might have been LED based or some new exotic lighting device. Anybody run into hum like line running top to bottom in Red Epic Raw files?

 

[Michael Romano]

I would look straight to the lighting and shutter speed combinations. Fluorescent and LED lighting can be big offenders but even an HMI light set to silent (instead of flicker free) can cause issues at normal frame rates depending on a multitude of factors. I wouldn't initially look to the camera unless it repeats with that body under different lighting scenarios.