Andrew Fildes wrote:
> ............
> No one mentioned vignetting I think - it can be a problem - I like to
> think of the edges of the frame as being stretched out to form a
> rectilinear image and so there's distortion and the light gets
> 'thinner'.
>
Take a look at the two images with vignetting corrected in the page I
just posted about perspective.
http://www.moosemystic.net/Gallery/tech/Lenses/Perspective/Perspective/
The vignetting correction is simply by eye with a couple of sliders, so
it may be used with images from any source.
> There are some programs which will correct for distortion as i
> remember - they were discussed on Luminous Landscape - but they have
> algorithms for each lens so there may not be a 'repair' available for
> heritage lenses.
PTLens also has a database of DSLRs and lenses that will correct linear
distortion. Works very well. Faced with a lens not in the database, one
may take test image(s) and send them in for analysis and addition to the
database. He doesn't do old film SLRs, but I notice entries for the
Schneider 28 mm PC lens and Hartblei 35/2.8 PC lenses.
Considering the number of Zuiko super-wides being used on FF Canyon
bodies, I suspect he would add those if asked and given sample images
meeting his specs.
Absent that, one may use an image from a MF lens with clear lines in it
and simply browse through the wide angle lenses to find one that does a
good job, then note it for future use.
> They seem to do a great job on straightening something like a Canon 16mm
> fisheye from what I've seen.
>
Fisheye correction in PTLens is outside the database and done manually
with sliders.
At $15, PTLens is a steal.
Moose
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