I need some help with exposure settings for soft nd grads... I am new to this and a little confused.
As I understand it a 0.3 nd grad equals one stop under, 0.6 two stops, 0.9 three stops etc...
So I set up my camera without filter at f5.6 1/60 sec... In aperture priority mode. I slide 0.6 2 stop filter into position and the camera stops down to 1/30 sec ( which is only one stop) I take a shot and compare with image without filter and yes the clouds have darkened slightly. However, this is a two stop filter so I switch to manual mode and stop down to 1/15 sec keeping aperture at f 5.6, two stops down from the original reading of 1/60 sec @ f 5.6. But this time the sky doesn't darken it actually gets lighter and the histogram shows the exposure is too far to the right with highlights off the chart so to speak.
What am I doing wrong and why is a two stop filter showing a better image when only stopped down by one stop?
Any help welcome.