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54
Aperture range graph
e aperture range for macro lenses is displayed on page 26 (TTL), and page 34
(Manual ash). e aperture ranges described here are for lenses other than macro
lenses, or when the subject distance is large.
TTL ash metering
Flash-subject
distance
M
in. Aperture lines
Aperture
Max. Aperture lines
Min. Aperture lines
Max. Aperture lines
e following explains how to obtain the aperture range using the two twin ash
units with a 1.5 m ash-to-subject distance and at ISO 100.
1 Draw a v
ertical line upwards from the ash-to-subject distance until it reaches
the minimum aperture line ().
2 Draw a horizontal line lewards from until it reaches the vertical ISO line
corresponding to the camera used ().
3
Draw a di
agonal line from upwards and lewards. e result indicates the
minimum aperture that will provide the proper exposure ().
4
e m
aximum aperture can be obtained in the same way by using the maximum
aperture line ().e results of both calculations will give the usable aperture
range for obtaining the proper exposure ().
In this case, the proper exposure can be obtained by setting the camera’s aperture
from maximum to f/16.
e dot
ted lines are employed when only one twin ash unit is used.
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