----- Original Message -----
From: "dave o'brien" <[EMAIL PROTECTED]>
To: "Pentax List" <[EMAIL PROTECTED]>
Sent: March 17, 2001 3:52 AM
Subject: 49mm reverse adapter for 6x7
> I've just acquired a 49mm Reverse Adapter for 6x7. It looks
nice so
> far - great magnification.
>
> But I've realised that I don't know how to calculate the
exposure. My
> 6x7 has no TTL finder and I've no idea of the adjustments
required.
> Looking through it with a variety of lenses, I'd guess that
the focal
> length of the reversed lens in important, as well as the
f-stop.
>
> Can anyone give me any advice?
I suspect you are going to have to do a calculation involving
the magnification ratio to come to some sort of an exposure
compensation. Unfortunately, the math eludes me. Something about
inverse square law comes to mind.
William Robb
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