>>4468401I'm inclined to just say that sounds retarded and move on, but there's a simple way to test it yourself.
Take all filters off your camera and set it to M. Keep the camera stationary, on a tripod or just sat on a desk looking at something that isn't changing.
Set the exposure to -+0 (i.e. middle of the light meter; correctly exposed) then screw on your ND4.
Check where the light meter goes after you put the filter on. If it's an ND4 that blocks two stops, your shot should read as two stops underexposed now.
I say this so you can test it yourself instead of relying on random internet guy (me), but my final rebuttal is what do you think an ND1000000 is? Do you reckon it prevents a million stops of light coming through?