I am NOT a PROfessional photographer and photography is NOT my hobby
Specs say, 30m at ISO200 and 21m at ISO100.Originally Posted by Artosoft
If you set your camera to ISO200, the GN is 30m. Meaning for distance 1m, you can use Aperture f/30 (aperture = GN / distance ==> Aperture = 30 / 1m = f/30).
For distance 21m, you need aperture 30/21m = aperture ~f/1.4, or at ASA1600 = aperture ~f/4.
Yah, not necessary using ASA1600 if you have f/1.4 lens .
Last edited by Artosoft; 17th November 2006 at 10:52 AM.
Oops, yes that's GN.
So, if the formula is, f/stop (aperture) = guide number (GN) x ISO sensitivity factor ÷ Shooting distance (m/ft).
F = 21 (GN) x 1 (ISO 100) ÷ 6m
That's F3.5 aperture, for 6m range. Still useful for many cases, of course up ISO for further ranges.
Nikon is good for ISO800 (sensitivity x2.8).
That will be F = 21 (GN) x 2.8 (ISO 800) ÷ 21m
= F2.8 aperture, good for use on F2.8 and faster aperture lenses.
Wow, it's looking better and better. Must get it liow.
Last edited by azul123; 17th November 2006 at 11:23 AM.