My self made coupling
device was made from the protective plastic
eyepiece cover supplied with the Opticron
Fieldscope, with the closed end cut off
and a 28mm to 37mm stepping ring fixed
to the cut end.
Step 1 was to measure from the base of the
thread where the cover attaches to the scope
(see photo 2) to the top of the eyepiece
(see photo 3) in my case was 44mm. I then
added the thickness of the stepping ring
4mm, a total of 48mm.
Step 2 was to cut the eyepiece cover to
48mm and then fix the stepping ring to
the inside with epoxy glue. Fortunately
a near perfect fit, only a little trimming
was neccessary. (see photo 4) also (see
photos 7and 8) Photo 8 shows the threaded
end that attaches to the scope.
Photo 5 was set up to show the
coupling in relation to the eyepiece (
temporary fixed with blue tack ) prior
to screwing on to the scope in photo 6.
A tip to keep in mind is, that just before
the epoxy glue sets, attach the coupling
device to the scope and carefully screw
the camera to the 28mm threaded end. Then
ensure that the camera is lined up horizontal
to the scope. That is, that when you view
the LCD screen the horizon would be parallel
to the top edge of the screen. Try to
ensure that the stepping ring does not
move within the plastic sleeve when removing
the camera and just in case it does draw
a pencil line across the joint so that
it can be re-aligned.
You may have noted by
my measurements that I have a gap of 4mm
between the eyepiece and the camera lens.
I believe that this is the cause of the
vignetting you see in the test
photographs focal lengths 7.85mm to
13.8mm. If my eyepiece had been 2mm to
3mm less in diamiter the stepping ring
would have slipped over the eyepiece and
I would have had near glass to glass fit.
I am still experimenting with this and
am confident that I will come up with
a solution.
When attaching the camera to the scope
it is probably better to screw the adapter
to the camera first then to the scope
to avoid damage to the 28mm filter thread
on the camera.
I have made some enquiries
and found that a number of brands of fieldscopes
are supplied with protective eyepiece
covers, (unfortuneately not the Leica
or Swarovski but maybe the one you possess
now) and am sure that with a little initiative
and experimenting that you would be able
to manufacture a similar type of coupling.
The length to cut the cover determined
by the dimensions of the eyepiece and
the stepping ring size 28mm to ?--determined
by the diamiter of the eyepiece cover.
I can assure you it is a very safe and
secure way to attach the camera to the
scope. Also that the camera is perfectly
lined up centrally with the eyepiece
There are a number of adapters available that will attach the camera to the eyepiece of the scope. These are a couple that are popular.
There are adapters supplied by London Camera Exchange camera shops to suit most eyepieces. Very simple and neat design, basically an alloy tube with a thread at one end and made for the eyepiece that you use. Its a very compact adapter allowing it to be left attached to the camera ready to be attached to the scope's eyepiece when needed.
The Eagle Eye Optics Zooms 'Digimount' adapter. This adapter has been around for some time, but has now been revised with a direct 28mm thread instead of a 37mm thread that required a step-down ring to fit Nikon filter threads.