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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.
