Archived posting to the Leica Users Group, 2006/12/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 10:29 PM +0100 12/6/06, Philippe Orlent wrote:
>I was just remembering my ISO scale on the back of my MP:
>50-100-200-400-800- etc.
>
>But the zones in between are divided in 3 parts.
>
>So between 50-100: 50/3=16,7
>Between: 100-200: 100/3=33,33, which would put 160 at 100 and 2/3ds
>Two full stops under brings us at
>400 and 2/3ds
>Which is 400 + (800-400)x2/3= 666,7
>
>I may be wrong, but it looks like Leica logics to me.
>:-)
>Philippe
>
ISO is not continuous. It's only defined for the discrete progression
(from 100 to 3200) for 100, 125, 160, 200, 250, 320, 400, 500, 640,
800, 1000, 1250, 1600, 2000, 2500, 3200.
No numbers in between, ie, there is not 'ISO 300' or 'ISO 666'.
--
* Henning J. Wulff
/|\ Wulff Photography & Design
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