The TTL sensor in the 4T starts measuring as soon as the 1st curtain
is released. If the ambient light is not totally insignificant, it will
reduce
the flash by the amount of ambient light. If the SS indicator was on 1/30s
when the shutter was released, half an exposure will have accumulated
before the flash is fired; so the flash will be reduced by half.
The flash doesn't know to start measuring until it gets the signal to fire,
and while the flash is on, it greatly exceeds ambient; so it will always
give a full exposure. For higher levels of ambient light, you may have to
compensate.
I recommend running test series.
Paul
----- Original Message -----
From: "Richard F. Man" <richard@xxxxxxxxxxxxxx>
To: "oly" <olympus@xxxxxxxxxxxxxxx>
Sent: Saturday, December 14, 2002 5:37 PM
Subject: [OM] TTL vs. Auto on the OM-4T and Metz
> Is there a difference, result-wise, with these TTL vs. auto mode with the
4
> or 4T combined with the Metz 54? I understand the light reading is
> different - in auto mode, the flash's sensor reads the light whereas in
TTL
> mode, the camera reads the exposure OTF at "real time." Since the flash
> sensor position is usually higher than the camera, it may read differently
> (especially at close subject?). My question is besides that, is that any
> difference?
>
> Thanks
>
> // richard <http://www.imagecraft.com>
> <http://www.dragonsgate.net/mailman/listinfo>
> On-line orders, support, and listservers available on web site.
> [ For technical support on ImageCraft products, please include all
previous
> replies in your msgs. ]
>
>
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