Nikon SB-800 instruction manual Close-up flash operation, 100 200 400 800 1000, Coefficient m/ft

Close-up flash operation

■■■ Setting the built-in wide-flash adapter and adjusting the zoom-head position

1 Slowly pull out the wide-flash adapter all the way, and position it over the flash head. Then slide the bounce card back into place inside the flash head.

2 Press the c or d button to adjust the zoom head position to 14mm or 17mm.

• When the wide-flash adapter is set on the flash head, the power zoom function becomes inactive and the zoom-head position is adjusted to 14mm or 17mm. To adjust the zoom-head position automatically using the power zoom function, go to the Custom settings “Power zoom function using the built-in wide-flash adapter/Nikon Diffusion Dome” (p. 67).

•To slide the wide-flash adapter back into place, lift it and push it into the flash head as far as it will go.

■■■ Setting the aperture

Calculate the aperture by using this equation and table. To ensure the correct exposure, use an aperture smaller than the one obtained from the equation.

ISO sensitivity		25	50	100	200	400	800	1000
Coefficient (m/ft)		1.4/4.6	2/6.6	2/6.6	4/13	4/13	5.6/18	5.6/18
	f/stop	Coefficient ÷ Flash-to-subject distance

For example, at an ISO sensitivity of 100 with a subject 0.5m (1.6 ft.) away and the wide-flash adapter in place, the suggested aperture is:

f/stop 2 ÷ 0.5 = 4 (in meters)

f/stop 6.6 ÷ 1.6 = approx. 4 (in feet)

Therefore, you should use at least f/4 or an even smaller aperture, such as f/5.6 or f/8.

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