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Re: Wide lenses for 12x20 @ 300mm
Sandy King wrote:
> ...
> Full coverage begins at the point where
> you first see a round image through the lens when looking through the
> corners of the ground glass.
This can work for most lenses. However, I have a 90mm
Schneider-Kreuznach Angulon which looses focus before illumination even
when stopped at f-16, f-22, or f-32. It can be difficult to access fine
focus of a dark image on the ground glass. This has been an unpleasant
surprise when assuming image deterioration would occur at the same place
of illumination fall off.
A better determination of the coverage might be to look at a negative
made at Sandy's condition rather than the ground glass.
--
Jeffrey D. Mathias
http://home.att.net/~jeffrey.d.mathias/