your aperture and shutter speed is set as such that your metering is " Neutral " at the brightest area without ND filter ,
then u put the filter then u manually slows down the shutter speed by 10 stops ?
Sorry newbie here
that shot was without ND filter.
no, when i do test shot, i make sure the histogram is what i want it to be, the metering is easily fooled. pentax tends to underexpose by half a stop to one stop, so usually the metering will be roughly +0.5 or +1.0.
then yes, i put the filter, and make sure the focus is right, add 10 stops by myself... if beyond 30 seconds have to use bulb mode, then do the calculations, etc.