Archived posting to the Leica Users Group, 2005/06/17

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Subject: [Leica] Re: darkroom focusing
From: creativevisions at verizon.net (Michael J Herring)
Date: Fri Jun 17 05:52:31 2005
References: <p06110407bed6904447bc@[192.168.1.135]> <5034ac88a60433fe64b6c0d0599f0beb@earthlink.net>

Many zooms (including expensive Nikkors) also exexhibit this focus shift.

Mike
----- Original Message -----
From: "Feli" <feli2@earthlink.net>
To: "Leica Users Group" <lug@leica-users.org>
Cc: <lug@leicausers.org>
Sent: Thursday, June 16, 2005 2:12 AM
Subject: Re: [Leica] Re: darkroom focusing


> I'm not an expert on optics, but the Noctilux is one of the best
corrected
> lenses around and it has a serious
> focus shift...
>
> feli
>
> On Jun 15, 2005, at 7:18 PM, Herbert Kanner wrote:
>
>> I think focus shift is a myth. If the focus were to shift when stopping
>> down, this would indicate that spherical aberration is so poorly
>> corrected that the portion (a ring) of the lens that is active between
>> say f/8 (the enlarging aperture)and say f/2,8, the focusing aperture,
has
>> a marked;y different focus distance than the portion (a circle) from
the
>> center to the periphery at f/2.8.  If this were true, the lens would
>> suck; it would be noticeably fuzzy at f/2.8.
>>
>> Herb
>> --
> ________________________________________________________
> feli2@earthlink.net      2 + 2 = 4        www.elanphotos.com
>
>
> no archive
>
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information
>


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In reply to: Message from kanner at acm.org (Herbert Kanner) ([Leica] Re: darkroom focusing)
Message from feli2 at earthlink.net (Feli) ([Leica] Re: darkroom focusing)