When in manual mode, you use iso or shutter speed (as well as ND filter before takeoff) to set your exposure according to the histogram and the way the monitor looks. This is done using the right wheel on the TX. By turning it you increase or decrease iso or shutter speed, by pushing down on the wheel you switch witch one is effected by the wheel. It is crude but it works well.I have used ND8 and it looks like it should be ND16 so the green sugarbeet has all the color, now it has like water shine white on it from the above and I cannot get anything from it in post. I manage to get rid of the gray in post by increasing contrast. And it looks good for low fly video here but from the above the video simply does not have color, it is too bright I guess.
I dont get you guys who say that you work in manual mode and then you say that you change the exposure. I cannot change exposure in manual mode, only in Auto.
So when you go in manual mode you change ISO in order to get the EV to 0 ?
So before takeoff you decide on what ND filter to use (if any) then set exposure using histogram and it will stay set, the EV is not used in manual mode at all.
If you notice that the histogram looks wrong when flying, just adjust the shutter speed so it looks right, picking the right ND filter usually makes it possible to shoot 1/60, 1/80 or 1/100 shutter and get correct exposure for 30p. If out of that range land and change to a different ND, or remove it if it is too dark.
This is a not as nice as a real video camera with built in ND's and variable aperture but it works well enough. In the future we may see continuously variable ND filters like in the Sony FS5, that would be a very nice solution for MR's. This is a electronically variable ND not the dual polarizer type that is very problematic for several reasons, one being vibration that could cause it to change while flying. But some have reported using them successfully here and on other boards. I think the added weight is also a problem for the gimbal on the P3P's.