Archived posting to the Leica Users Group, 2001/05/09

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: RE: [Leica] Re: Konica facts
From: Henning Wulff <henningw@archiphoto.com>
Date: Wed, 9 May 2001 13:09:36 -0700
References: <9DC5E2ABE65BD54CA9088DA3194461D604A99D0C@BBY1EXM01>

At 12:09 PM -0700 5/9/01, Paul Chefurka wrote:
>On this issue of back focus - it's my understanding that wide-angle 
>lenses are more critical for back focus than long lenses, rather 
>than less critical.  Something about depth of field and depth of 
>focus being inversely related or something.  Can anyone enlighten me?
>
>Paul

It's not that wide angles are more critical; the f/stop is all that 
matters. However, while a 0.2mm increase in the back focus causes a 
35mm lens to focus at 6m instead of infinity, the same back focus 
error will cause a 135mm lens to focus at 90m instead of infinity. If 
they were used at the same aperture, one shot would look as fuzzy as 
the other.

- -- 
    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  /###\   mailto:henningw@archiphoto.com
  |[ ]|     http://www.archiphoto.com

Replies: Reply from "Jacques Bilinski" <jbilin@axionet.com> (Re: [Leica] Re: Konica facts)
In reply to: Message from Paul Chefurka <Paul_Chefurka@pmc-sierra.com> (RE: [Leica] Re: Konica facts)