> f/16 A+ A
> f/22 A- A-
> Note: Exceptional low contrast image detail stopped down; remarkable lack of
> vignetting wide open. One of the best Zuiko lenses.
>
> I found it remarkable that performance would peak out of f/16, since once
> would expect diffraction limited performance at that aperture.
>
> Gary Reese
> Las Vegas, NV
Diffraction is determined by the ratio of (light wavelength)/(size of opening).
A 100mm at f/16 has the same opening as a 50mm at f/8. The f64 School used
large format cameras, for which the typical lenses might be 300mm.
The 100mm/2 is a double Gauss design (originally 1896, I think), essentially
a scaled up 50mm. Among other things, that accounts for its somewhat startling
weight: it's got an awful lot of glass stuffed inside.
Paul Farrar
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