i am thinking of buying ND filter to create some super long exposure.
ve some doubts to clear.
1. ND4 is 2 stops, ND8 is 4 stops, correct?
2. exposure calculation after puttin on ND8
in aperture priority, scene requires 20 sec at F8 (w/o filter)
so, after puttin on filter, exposure is 20 x 2 x 2 x 2 x 2 = 320 sec, rite?
3. any other advise is much welcome.