JOHN DUGGAN wrote:
> B+H advertise a 49 to72mm step up adapter.....for about $6. Could this not be
> adapted/machined to fit?
>
To quote Wayne H from three weeks ago:
=========================================
"Really quite a simple operation. Buy yourself a 49->72mm step up ring, it
probably won't screw onto your 18mm because it needs to screw down into a
groove and the inside diameter of the stepping ring is too small. Use the
lathe to bore out the inside diameter until it fits into the 18mm's groove. The
stepping ring won't be as strong as when it started but probably no worse than
the Oly part. Depending on the depth of the stepping ring you may need to
extend the 72mm part so that mounted filters don't touch the front element.
You can do this by getting a cheap 72mm filter and removing the glass and
mounting this on the step up ring.
...Wayne
=========================================
and from 6/9/2007, including pics of a conversion, as referenced last month by
Chuck:
=========================================
A few weeks ago there was some discussion about the Olympus hood/filter
adapter for the OM Zuiko 18mm f3.5. I volunteered to bore out a 49-->72mm
step-up ring to see if it could be used as a substitute hood/filter adapter.
I obtained a cheap (about $US7) step-up ring from www.camerafilters.com and
bored the inside of the 49mm threaded section on the lathe from 45.2mm to
46.5mm (same ID as the Oly hood) which fitted perfectly on the 18/3.5 even
though the threaded section was 0.5mm longer than the Oly version. As the
step-up ring is flat the front element of the 18/3.5 still projects about
1.5 mm from the front of the ring so I added a filter ring from which I had
removed the glass. As the filter was a fairly thick the resultant hood is
about 2mm deeper than the Oly hood but allowed me to mount a thin Hoya on
top of the combination without getting any vignetting.
This link takes you to a page which shows a few images of the step-up ring
mounted on the 18/3.5:
http://lrh.structuregraphs.com/test/hood.htm
The bottom line is that it seems a substitute hood can be made fairly easily
if you can't find/afford the original Oly.
...Wayne
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