Nikon SB-30 - Manual (Page 20)

18
Manual flash mode
The SB-30’s flash output level can be set manually at M1/1, M1/8, or M1/32. In the Manual mode,
you must determine the correct exposure by calculation using a combination of the guide number,
shooting distance, and lens aperture.
• If the camera’s exposure mode is set to other than Aperture-Priority Auto (A) or Manual (M), the shutter may
not be released, depending on the cameras in use.
Guide number (m/ft.) and ISO sensitivity
ISO sensitivity 25 50 100 200 400 800 1600
M1/1 8/26 11/36 16/52 22/72 32/105 45/148 64/210
Flash output level M1/8 2.8/9 4/13 5.6/18 8/26 11/36 16/52 22/72
M1/32 1.4/4.6 2/6.6 2.8/9.2 4/13 5.6/18 8/26 11/36
Flash output level
M1/1 5/16 7.1/23 10/33 14/46 20/66 28/92 40/131
(with wide-flash adapter in place)
M1/8 1.8/5.9 2.5/8.2 3.5/11 5/16 7.1/23 10/33 14/46
M1/32 0.9/3 1.3/4.3 1.8/5.9 2.5/8.2 3.5/11 5/16 7.1/23
• To obtain the correct exposure, use the following equations to determine the aperture and guide number to match the
flash shooting distance.
f/stop (aperture) = Guide number (GN) ÷ Shooting distance (m/ft)
Guide number (GN) = Aperture x Shooting distance (m/ft)
• For example, when shooting a subject at a distance of 2.5m (8.2 ft), at an ISO sensitivity of 400 and a lens aperture of f/2.8:
Guide number = 2.8 x 2.5 = 7 (in meters) or 2.8 x 8.2 = approx. 23 (in feet).
Therefore M1/8 is the correct flash output level with the wide-flash adapter in place.
• Likewise, when shooting a subject at a distance of 4m (13 ft.), at an ISO sensitivity of 400 and M1/1 flash output level
without using the wide-flash adapter:
f/stop = 32 ÷ 4 = 8 (in meters) or 105 ÷ 13 = approx. 8 (in feet). Therefore, f/8 is the correct lens aperture.