Archived posting to the Leica Users Group, 2005/06/15

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Subject: [Leica] Re: darkroom focusing
From: feli2 at earthlink.net (Feli)
Date: Wed Jun 15 23:12:33 2005
References: <p06110407bed6904447bc@[192.168.1.135]>

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


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Replies: Reply from creativevisions at verizon.net (Michael J Herring) ([Leica] Re: darkroom focusing)
In reply to: Message from kanner at acm.org (Herbert Kanner) ([Leica] Re: darkroom focusing)