[Leica] Biogon SWC (lack of) distortion

[roark.paul at gmail.com (Paul Roark)]

Looking at the difference between retrofocus (e.g., Distagons) and
more symmetrical (e.g., Biogons) wide angle lenses, consider also the
usual corner performance up close.  I have never had the pleasure of
having a Hasselblad super-wide, but from what I know, the Biogons all
share some of the same qualities that have made them so highly thought
of.   See this test shot I made comparing the 18 mm Distagon ZM with
the 21 mm Biogon on the M9:
http://www.paulroark.com/BW-Info/Corners-18-v-21mmZM.jpg.  The Biogons
have more light fall-off, but they are very sharp and distortion
(barrel, etc.) free.  Obviously they have the perspective exaggeration
of any wide angle.

Avoiding the typical close-focus corner softness of retrofocus wide
angles is a major reason I switched to rangefinder cameras.

Paul
www.PaulRoark.com