Pentax K-500 Operating Guide

253

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The following equation calculates the correct aperture value.

Aperture value F = Guide number ÷ Shooting distance

Example:

When the sensitivity is ISO 200 and the shooting distance is 4 m:

F = 17 ÷ 4 = approx. 4.2

If the resulting number (4.2, in the above example) is not available 

as a lens aperture, a smaller number that is closest (4.0, in the 

above example) is generally used.

Calculating Aperture Value from Shooting Distance

K-500.book  Page 253  Friday, June 14, 2013  2:29 PM