I am brand new to video (moving up from my still work) and tried out my new 4x4 ND filter set today with the embarrassing and simple test of holding them in front of my light meter Sekoinc L-358 to get a reading and then to the camera to check the exposure in a quick live view & recording test. I set the light meter to cinema mode and to the same settings as the camera, then with my ND filter in front of the dome I got a reading of F-11. On my camera test the with the filter in front of the lens I didn't get a proper exposure until I adjusted it open to F-6.3.
Anyone know why this would be? I was hoping to use the meter as I do for my still work where the readings are spot on. Thought it would be nice to get a feel for my aperture options for video by holding the ND filters over my light meter.