Archived posting to the Leica Users Group, 2008/12/14

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Subject: [Leica] Re: M8 upgrade - 90 Cron APO focusing problems now Question????
From: len-001 at verizon.net (Leonard Taupier)
Date: Sun Dec 14 08:08:54 2008
References: <200812140550.mBE5oDXn017292@server1.waverley.reid.org> <BLU121-DS62FCEF56DE86977ED4A00D4F70@phx.gbl>

Aram,

SLR's can have the same problem but primarily with auto focus issues.  
I bought a nikon AF 105 f2 a couple years ago that had terrible back  
focus issues on my D2H. I had to return the lens.

Len


On Dec 14, 2008, at 10:37 AM, Aram Langhans wrote:

> Thanks to all for the explanations.  Film/sensor and lens design  
> all play a
> role, it looks like.  I would think the film vs. sensor would also  
> effect
> SLR's, since focusing is not on the film itself.  But shouldn't the  
> focus
> shift as you stop a lens down also effect an SLR?  I am assuming  
> that the
> SLR focuses (auto or manual) with the lens wide open, then stops  
> the lens
> down to take the photo.  So, this should have the same effect as say
> focusing accurately on a rangefinder for whatever aperture the  
> coupling is
> accurate, then taking the picture at some different aperture?  Does  
> this
> sound right, or is my retired brain not working correctly?
>
> Aram
>
>> Date: Sat, 13 Dec 2008 19:00:04 -0800
>> From: Peter Klein <pklein@threshinc.com>
>> Subject: Re. [Leica] M8 upgrade - 90 Cron APO focusing problems now
>>      Question????
>> To: lug@leica-users.org
>> Message-ID: <5.1.0.14.2.20081213185418.0276ce40@mail.threshinc.com>
>> Content-Type: text/plain; charset="us-ascii"; format=flowed
>>
>> In my previous post, I put in an ASCII diagram illustrating focus
>> tolerance
>> on film vs. a sensor, and messed it up.  Here is a screen clip which
>> will
>> show things correctly:
>>
>> http://users.2alpha.com/~pklein/temp/FilmVsSensorFocus.gif
>>
>> --Peter
>
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In reply to: Message from leicar at q.com (Aram Langhans) ([Leica] Re: M8 upgrade - 90 Cron APO focusing problems now Question????)