On Fri, 02 Feb 2001 15:53:50 +0100 Gerard Maas <[EMAIL PROTECTED]>
writes:
> Hi all,
>
> Yesterday I realized something quite extrange:
> I've the Extension Tubes from Kenko: 12, 24 & 36mm (sold as a kit)
> and the 25mm.
> Casually looking inside them I saw that the 25mm do has electronics
> inside. It has a chip connected to the pins. (sorry, no electronics
> knowlegde as to know for what!) all other Kenko's are just plain
> "bridges" from one side to the other.
>
> Some time ago I asked "what about the canon". The answer I got then
> was that they are also "only" a bridge.
>
> Now, I'm wondering.... What is this chip for ? once again, What
> about canon?
The Canon 25mm tube has a chip inside, the 12mm does not. If you mount
the 25mm tube on a body with no lens attached and fire the shutter, the
body "locks up" - the 12mm tube doesn't do that. How about the Kenko
tubes?
BTW - I think the chip tells the camera that a tube is in use and to
correct for metering errors.
Dave Herzstein
[EMAIL PROTECTED]
http://www.kjsl.com/~dave
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