if 1/500 is 10 seconds then whats the calc?

[AshleyKent]

what stop do i have if 1/500 is the same as 10 seconds with the filter on... to get the same histogram?

explination of stops would be appriciated aswell

 

[CSB]

If the aperture is unchanged you have a 12 & 1/3 stop filter, unlikely as most nd filters are 9 or 10 stop

F stop explanation

 

[Uneducated_Rick]

1/500 - starting point

1/250 - 1 stop
1/125 - 2 stops
1/60 - 3 stops
1/30 - 4 stops
1/15 - 5 stops
1/8 - 6 stops
1/4 - 7 stops
1/2 - 8 stops
1s - 9 stops
2s - 10 stops
4s - 11 stops
8s - 12 stops
16s - 13 stops

as you've now got 12s it is somewhere between 12 and 13 stops as CSB said above. The wiki link will explain it more for you and hjow to work out 1/2 and 1/3 stops

 

[Alastair]

12 stops sounds about right for a Shade 9. A shade 10 is 13-14 stops by most people's calculations.

 

[AndyB1976]

Caculator until you can do it in your head.....

http://imaginatorium.org/stuff/stops.htm