RE: Digital slide camera, was Re: off-topic digital camera suggestions

From: Etienne Garbaux ^lt;[email protected]>
Date: 12/14/04-08:35:58 PM Z
Message-id: <p05210600bde539788f67@[192.168.1.100]>

Darryl wrote:

> My education happens to be somewhat "vintage." Could you describe some
> of these cobbled solutions? I've gotten the use of our schools Canon
> 20D and am quickly learning how little I really know. Loving the ride
> on the learning curve...

I've used most every technique suggested by the imagination, from cardboard
tubes and gaffers' tape to custom machined adapters. The easiest is using
bellows with unmounted lenses (mine are an old Spiratone T-mount bellows
with an EOS adapter). Depending on how you affix the lens (how much
projects forward and how much projects rearward from the front mounting
board), you can usually focus to infinity with lenses of about 60mm and up.
I have been accumulating threaded rings and flanges of various sorts for
decades, so I can usually adapt pretty much any barrel-mounted lens to the
bellows' front (female) T-mount, or to the sheet-metal front plate after
removing the T-mount flange. For shorter focal length lenses, just the EOS
T-mount adapter, or the adapter and part of a T-mount extension ring set,
is ideal.

More complex methods include a focusing helix originally made for a 6x4.5
cm SLR -- maybe a Mamiya or Pentax? -- which I permanently mounted to an
EOS T-mount adapter. This can get many lenses close enough to hit the
mirror. For really short stuff (Heliar 15 and 12mm, Hologon 15mm, Nikon
fisheyes, etc.), you need a real mirror lock-up. (The 10D has mirror
lock-up, but it releases the mirror at the end of each exposure -- you can
prevent the mirror from hitting the lens on its way up, but not on its way
down.)

Finally, for really tough cases, I machine the adapter I need using a lathe
and milling machine.

Best regards,

etienne
Received on Tue Dec 14 20:46:47 2004

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