Nikon SB-21 instruction manual Select and set aperture, For external power source For batteries

For external power source -

_	For batteries	_
	inside the controller

4. Select and set aperture.

When the S8-21 is powered by batteries inside the controller, usable apertures are indicated by the aper· ture indicator lines (excluding narrow line-end) which intersect the reproduction scale.

When the S8 -21 is powered by the external power source LA-2 or LO -2, usable apertures are indicated by the aperture indicator lines (including narrow line-end).

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For a high reproduction ratio, use the smallest \

possible aperture for greater depth of field. I

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With the lens in reverse position :

For the desired reproduction ratio, follow the line from the red reproduction ratio scale and read the usable apertures.

For example, when the S8-21 is powered by batteries inside the controller, to obtain a 4x (4 :1) reproduction ratio with ISO 100 film and Micro -Nikkor 55mm f/2 .8 lens in reverse position, use apertures from f/2 .8 to fill .

With lens in normal position:

For desired reproduction ratio, follow the line from the white reproduction ratio scale and read the usable apertures.

For example, when the S8-21 is powered by batteries inside the controller, to obtain a 1: 10 reproduction ratio with ISO 100 film and Micro-Nikkor 55mm 112 .8 lens in normal position, use apertures from f/4 to f/16.

For usable apertures with a reproduction ratio lower than 1: 10, see page 40.

When the S6·21 is powered by external power source:

For example, to obtain 4x reproduction ratio with ISO 100 film and the Micro-Nikkor 55mm f/2.8 lens in reverse position, usable aperture extends to f/2 .8 to f/16 .

I	------ ..._---- ...	\
	With the Condenser Adapter SW·S
I	attached:	I
	The usable aperture range shifts to 1/2 stop I
I smaller. For example, to obtain 4x reproduc-		I
I tion ratio with ISO 100 film and the Micro-		I
I	Nikkor 55mm f/2 .8 lens in reverse position,
		I
\ ...	use apertures from f/2 .8+ 1/2 to fill + 1/2 .
	------------*I

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