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From: hds@fred.UUCP (David Scarbro)
Newsgroups: net.rec.photo
Subject: Re: Zooming during an exposure.
Message-ID: <121@fred.UUCP>
Date: Thu, 6-Mar-86 11:32:38 EST
Article-I.D.: fred.121
Posted: Thu Mar  6 11:32:38 1986
Date-Received: Sat, 8-Mar-86 22:37:51 EST
References: <1278@cvl.UUCP>
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Organization: NBI,Inc, Boulder CO
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>   During the zoom the effective aperture of this lens changes. My question
> is if the automatic exposure system will respond to this change by adjusting 
> the shutter speed DURING THE EXPOSURE - the shutter has already been released
> and the exposure is in progress when the aperture changes because of the
> effect of zooming with this lens. Does the metering system select a shutter
> speed at the instant  the shutter release is depressed and "freeze" it for the
> duration of the exposure ? Or does the system respond to changes during the
> exposure ?

Nikons don't meter during exposure.  Olympus is the only maker of SLR's that
I'm aware of that meter "off-the-film" during exposure.

A simple way of testing this is to meter off a dim (but not stupid subject)
at a small aperature setting (to guarantee a long exposure).  Then begin the
exposure and point the camera at a bright subject.

David Scarbro
Integrated Solutions (an NBI Company)
..!nbires!fred!hds