WKato@xxxxxxx wrote:
>
> Michael A. Covington wrote:
>
> << > > I was asking because in an book on Novoflex lenses they showed how to
> > > adjust this lenses from terrestial to astronomical infinity. Maybe the
> > > atmosphere is a more limiting factor in horizontal, than in vertical
> > > direction? So the coloured fringes might be a product of not proper
> > > infinty? Just a guess...
> > I haven't a *clue* what they're talking about. Infinity is infinity! Do
> > you still have the book? Can you quote what they say?
It´a 1978 book from D. Gabler about Novoflex gear (bellows and fast
focusing lenses). In one chapter he describs basic adjustment of
infinity for this lense (sometime necessary, because the lenses can be
used with several adapters). He recomends to focus on an structure more
than 1000m away (to close for an 400mm/5.6, for my taste, my 200mm Zuiko
don´t reach infinty at 1800m).
In an later chapter on photos of the moon, he explains, that terrestical
infinity (aprox. 1000m) is not suficent for sharp photos of the moon,
"sky-infinity" should be reached by unlocking the the focus stop.
> Maybe it's an adjustment for optimization for sharpest focus for either
> terrestial distances, like between 50x, and true infinity.
I guess so, many times your are not able to reach infinty due to
atmospheric irregularities (haze, heat movement) or at least you will
not reach a sharper focus with infinity. And you have to consider the
time of the writing, 20 years ago there where no focusing screens like
the series 2 of Olympus and not many cameras had an finder as bright as
an OM-1 (the camera the author recomends) the films where much grainier,
so it was much more dificult to focus (and specs where more generous?)
To infinity I found in an other book some interesting remarks: If the
stars would be realy "infinty" we couldn´t focus on them and see them,
because the result where points of no extension. Actualy "infinity" is
where our eyes could not decipher any diference between two points of
different distance from us (like DOF), just a question of resolution.
Huh, enough rambling I guess we should stop this thread before it get´s
to philosophic.
Richard
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|