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Re: [OM] WA corner distortion?

Subject: Re: [OM] WA corner distortion?
From: "John A. Lind" <jlind@xxxxxxxxxxx>
Date: Wed, 11 Oct 2000 17:56:33 +0000
At 16:21 10/11/00 , you wrote:
>Is there a word or term for the type of distortion I see in photos taken 
>with some wide angle lenses, exhibited by a kind of 'smearing' of details in 
>the corners while the edges are still sharp?
>-----------
>Lex Jenkins
>---------------------------------------------------------------------
>2b XOR -2b ... that's the equation - Ur Amblet, 'The Very Bad Quarto'
>=====================================================================

Ummmm, a rectilinear lens?  ;-)
It's how a flat plane in space gets mapped to a flat plane of film (unless
there's unintended edge softness, barrel, pincushion, falloff, etc.).

The Zuiko's down to 18mm are all theoretically rectilinear, which means
they will preserve perspective angles, not areas.  A true spherical
fisheye, such as the 16mm or 8mm theoretically map a hemisphere in space to
a flat plane of film (much like a polar map does) and preserves area, not
angles.  As you move from the lens axis outward, you can preserve one or
the other, but cannot preserve both.

With portraits, especially groups where you cannot back up enough and are
forced into using a rectilinear WA, it's why you definitely do not want
someone's head in a corner!

-- John 

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