Re: [Rollei] Define "Contrast" and "Sharpness"

[Jan Böttcher <jab]

yes, a tautology is something tautological!

Id rather say:
contrast means measuring how dark(-grey) black subjects/areas) will be reproduced
and how light(grey) white areas/subjects will be reproduced, (good contrast lense will
reproduce black as black, not dark-/medium-grey, and white as white not ligth-/medium
grey),
and sharpness/resolution refers to the finest pattern reproduceable disregarding the fact,
that black has turned into 49.5%reflection and white has turned into 50.5% reflection,
the finer the pattern got.

The rest in fact is best seen in examples as in Zeiss's propaganda pamphlets.
Jan

Dirk-Roger Schmitt wrote:

> o.k.
>
> very easy.
>
> You just need a graph of contrast vs spatial frequency or vs. spatial
> wavelength for each lens to discuss differences.
>
> That is the only way.
>
> At 23:49 14.02.2002 -0800, you wrote:
> >Okay all you optics nerds. Here yer chance to show some of us lesser
> >scientific underlings a thing or two. My question is this-
> >    What exactly is contrast,  and sharpness. Explain how they relate to
> > each other in the context of  a discussion of a lens - (example - the
> > differenc ebetween a id 50's Tessar, and a F series Type 4 Planar) -
> >Roberto
> >

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