Dear all,

I have Vivid Polar pro lenses ( https://www.amazon.com/gp/produc ... e?ie=UTF8&psc=1 ). I am using the ND16/PL on a Phantom 4 pro . We are shooting still pictures with the camera pointing down vertically (at Nadir) and the drone moving horizontally at a fixed altitude. How should the polarizer be rotated to remove the reflection from the grass as much as possible?

Thank you

Polarizers are awkward to use on a drone because they have to be oriented to the sun.
If you get it properly set up and turn your drone left or right, it's not going to be properly aligned relative to the sun.

I typically look through the polarizer off-camera and rotate it while facing the same direction and angle I intend to take the picture at.  While rotating, note the position of the polarizer when you find the least amount of glare and mount it on the camera at this same rotational position.  You can often use the lettering on the outside of the polarizer, or make a small mark with a pencil for a temporary rotation marker.  If you see little or no change while rotating and looking through it, try different angles, lighting conditions, or time of day.  In certain conditions, they simply do no good at all, and you are best to just use the clear factory cap, or an ND filter.

I have given up trying to polarise my filter.   Flight changes need constant filter changes - - mmm  not easy in flight !??
I have a set of ND/CPL filters,  4,8,16.  Now I just use one position/setting for the CPL.