[LargeFormat] 5x7 Lens Information

[Richard Knoppow]

At 05:49 PM 08/25/2002 -0700, you wrote:
>Clive,
>
>     The 165mm Angulon probably doesn't provide as much image circle as
>the 190mm Kodak Wide Field Ektar though it is wider.  Is it f/6.3?
>
>Rich
>
  The Wide Field Ektar is a better lens although it doesn't have as much
coverage as an Angulon. Angulons are about the same as a WA Dagor, maybe 90
degrees stopped way down. The circle of illumination is larger, maybe as
much as 102 degrees but the image quality beyond maybe 85 degrees isn't
that great. 
  The wide open speed is for composing only.
  A W.F.Ektar has about 85 degrees stopped down, not much smaller, but
image quality is good over the whole field. Also, it doesn't have the zonal
spherical typical of the Dagor type lenses, which the Angulon is. 
  The WF Ektar is also exceptionally well color corrected. Kodak seems to
have made the Ektar seeries of lenses mainly to encourage the sales of
color film. 
  Modern Biogon type W.A. lenses are better than any of the older type but
they are larger and heavier. Some modern WA lenses have coverage well
beyond 100 degrees. 
----
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com