re: Inverse Vignetting?

[P3D Dr. George A. Themelis <fj834@xxxxxxxxxxxxxxxxxxxxx>]

>>Allan Carrano>There were three slides that appeared to be
>poorly focused in the central area of the frame, but were
>sharp (or sharper) in the peripheral area, a sort of
>inverse vignetting.

I think the term vignetting is used for loss of light at the edges, not
loss of sharpness.  I cannot think of anything that would cause this,
except for what Dave suggested:

>My most likely guess would be lens fogging - was it a moist day?


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