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[OM] Real time

Subject: [OM] Real time
From: Patrick Greenlee <patrickg@xxxxxxxxxxxxxxx>
Date: Thu, 14 Jan 1999 07:23:11 -0700
><< Now, how each one defines real time is relative, as ol' Einstein once
>said... :) >>

>THAT's the question!

>When I hear "real time" I assume it's during exposure.  So, the OM-4, doesn't
>have "real time". as everyone knows.  (to my definition, anyway).

>George S.

Real time is a frequent bone of contention among data analysis types.  One
man's real time is another's "near" real time or ...  A useful definition
or way to characterize real time for data/signal processing problems
(automation of exposure is in this category) is irrespective of speed or
actual duration if there are hard deadlines to be met which if not met
constitutes system failure often with but not necessarily always having a
cyclic or repetitive nature then it is a real time system.  Real time makes
no implication of accuracy.

So what does that imply regarding a camera that adjusts exposure value
components (shutter and/or aperture) dynamically in response to the scenes
changing ambient conditions until the shutter is released at which time
those values are fixed for that exposure?  Seems such a system could still
be rightfully called real time.  It would be more prone to system failure
since if the scene's ambient conditions varied significantly after the
shutter was released a "bad" exposure could result.  This is not to say
that an improved system, one that varied the exposure value components
during exposure with "fast enough" response time to ensure a "good"
exposure under some arbitrarily varied conditions isn't a better system and
extends real time control into the time region of the actual exposure, it
still, like the previous system, is "real time."

What camera can we afford that varies focus, shutter speed and aperture
(and maybe flash power) dynamically during the exposure fast enough to
prevent "a bad frame."

Meanwhile I will struggle along with my OM-1N and OM-2N bodies.

Patrick

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