Soenke
I'm not one to hold back on detailed, quasi-scientific explanations if I can
think of
one. On the other hand, it would not do to BS any of the OM List - out of
respect of
course, but also because too many of our ether-friends are clever enough to see
through
rubbish explanations!.
I don't know.
However, all of my long exposures with my OM4 (and with the OM2SP that preceded
it)
have worked beautifully, just as good old Franz Pangerl said they would when he
was
pooh-poohing Olympus' nominal limit of 60 seconds on OTF exposures. In other
words,
bracketing for all but the most fastidious (or experimental) is unnecessary.
Soenke Jansen wrote:
> Chris Barker wrote:
>
> > Franz Pangerl, in his book "The World of OM Systems" reckons that it is
> > because of
> > the Silicon Blue Cells which do the measuring for OTF exposures (in the OM2
> > at
> > least). He reckons:...if the silicon photodiodes only receive weak
> > measuring
> > currents [in low light exposures], then they react with successively
> > extended
> > exposure. This produces an unintentional but useful side-effect - a partial
> > balance of the reciprocity law failure."
> >
> > NB my square brackets.
> >
> > Chris
>
> Oops!
> Thanks Chris. But in a way this is nasty too (not your citation of
> course, but the SBCs overreacting). Because that means, if I follow the
> tables and graphs, the film producers give for
> 'reciprocity-failure-compensation' I'll overcompensate. And bracketing a
> 4min exposure takes you to something like a quarter hour you spend with
> that motive in which time the light situation will have changed for
> sure. Any solution in sight?
> Dumbfundled,
> Soenke, Hamburg
>
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