Archived posting to the
Leica Users Group, 2006/12/07
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Subject: [Leica] Math Question
From: walt at waltjohnson.com (Walt Johnson)
Date: Thu Dec 7 15:34:35 2006
References: <7.0.1.0.2.20061206152403.027b4508@infoave.net> <45772DC5.3040508@mcclary.net> <23C63C29-1E1D-43D6-A946-45C580F2326E@pandora.be> <4577300C.7000108@mcclary.net> <F04C2DAF-1C77-416C-ACC7-72A31E62F94F@pandora.be> <p0623090dc19e3edfaa21@[10.1.16.133]>
Doesn't it have something to do with logging rhythms. in .3 increments?
Henning Wulff wrote:
> 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'.
>
Replies:
Reply from datamaster at northcoastphotos.com (Gary Todoroff) ([Leica] Math Question)
Reply from henningw at archiphoto.com (Henning Wulff) ([Leica] Math Question)
Reply from henningw at archiphoto.com (Henning Wulff) ([Leica] IMG: Another FF)
In reply to:
Message from images at InfoAve.Net (Tina Manley) ([Leica] Math Question)
Message from harrison at mcclary.net (Harrison McClary) ([Leica] Math Question)
Message from philippe.orlent at pandora.be (Philippe Orlent) ([Leica] Math Question)
Message from harrison at mcclary.net (Harrison McClary) ([Leica] Math Question)
Message from philippe.orlent at pandora.be (Philippe Orlent) ([Leica] Math Question)
Message from henningw at archiphoto.com (Henning Wulff) ([Leica] Math Question)