Difference between revisions of "Guide number"

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The '''guide number''' is a value indicating the strength of a flashlight. According to Andreas Feininger the guide number helps finding the right aperture for flashlight exposures with the formula
 
The '''guide number''' is a value indicating the strength of a flashlight. According to Andreas Feininger the guide number helps finding the right aperture for flashlight exposures with the formula
 +
 
<span style="font-family:Courier">
 
<span style="font-family:Courier">
 
aperture=<U>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;guide number&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</U><br/>
 
aperture=<U>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;guide number&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</U><br/>
 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;distance between flash and image subject
 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;distance between flash and image subject
 
</span>
 
</span>

Revision as of 17:38, 28 May 2006

The guide number is a value indicating the strength of a flashlight. According to Andreas Feininger the guide number helps finding the right aperture for flashlight exposures with the formula

aperture=                    guide number                
         distance between flash and image subject

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