Re: How to know focus free setting of large format lens?

[Randy Vaughn-Dotta <randyd@xxxxxxxxxxxxx>]

Yadri,

Last I heard, infinity was considered to be 100x
the focal length of the lens for large format.
So for the 120mm thats 12,000mm, or 472.44"
or 39.37 feet. For the 180mm its 59.05 feet. the
90mm should be 29.52 feet.

Randy

>a 120mm and a 180mm.
>
>However, for quick shooting without wanting to focus, I want to be able to
>set the lenses at "infinity", so that I do not need to focus and can just
>increase my depth of field by using smaller f-stops.
>
>Does anybody know at what distance I can consider these lenses focused at
>infinity?
>
>The 90mm lens on my Linhof 617 focuses at infinity beyond its 40 feet mark,
>at about 50 or 60 feet, which is about 15 meter.
>
>The 120 must be around 18-20 feet
>The 180mm around 80 feet (twice the distance of the 90mm????)
>
>To anyone who can helkp, thanks in advance.


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         Randy Vaughn-Dotta, Photographer
          California State University, Fresno
               Academic Innovation Center
                 Telephone, 559-278-4656
    E-Mail,  randy_vaughn-dotta@xxxxxxxxxxxxx
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