Archived posting to the Leica Users Group, 1999/07/07
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On 7 Jul 99, Nathan Wajsman wrote, at least in part:
Good observation. Even after putting the straight edge on it, it still
looks a bit curved, though. Of course, being night time, we dont
know for sure where the horizon is or if the lights are truly
representative of the horizon.
Still, could it be the curvature of the earth, assuming no barrel
distortion, at that distance?
> Roger,
>
> I do not believe it is lens distortion. The horizon is actually
> straighter than it first appears (try putting a ruler against it). It
> appears curved because there is less light at the edges, especially on the
> left side of the picture.
>
> Nathan
>
> Roger Beamon wrote:
>
> > you LHSA types out there check Brian Bower's article in the
> > current VIEWFINDER Volume 32, number 2 and tell me
> > something. Is the lower picture on Pg. 18 showing the curvature
> > of the earth that is apparent with a very wide lens from such a
> > wide vantage point or is it a bit of expected barrel distortion from
> > such a lens, OR, a combination of both?
> >
> > I guess my question is, how rectilinear is rectilinear? My guess is that
> > the lens in that shot was set up pretty plumb.
- --
Roger
mailto:roger@beamon.org
The greatest of all gifts is the power
to estimate things at their true worth.
-- La Rochefoucauld