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Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Thu Apr 14, 2016 2:35 am
by carlh6902
Attached is a link showing how I added a simple darkfield stop to my Olympus BH-2 scope, by using a Nikon (Labophot) abbe condenser. This also applies to Nikon scopes.

Edit 5/9/21: Replaced outdated link with a link to the master index, which always contains the latest documents.

https://drive.google.com/folderview?id= ... P4pd4whvvs

Carl

Re: Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Thu Apr 14, 2016 3:22 am
by zzffnn
What I did was:

1) take a Nikon dovetail condenser adapter (I have seen two versions of such adapters, or you can take off the lower part of a Nikon dovetail condenser as adapter);

2) glue a dedicated oil darkfield condenser to the adapter concentrically.

Resulting images are pretty good. Darkfield works up to 97x NA 1.25 oil objective stopped down with funnel stop (to NA around 0.8-0.85), or an iris immersion objective with NA set to NA 0.9.

I have also glued a NA 1.4 condenser, and used Lego spacers to make a filter slot right above the dovetail condenser adapter.

Forum member gekko has also done something similar to what I did, with his Optiphot's dovetail condenser mount.

Yes, Olympus BH2 has a very similar condenser mount.

Re: Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Thu Apr 14, 2016 3:51 am
by carlh6902
zzffnn wrote:What I did was:

1) take a Nikon dovetail condenser adapter (I have seen two versions of such adapters, or you can take off the lower part of a Nikon dovetail condenser as adapter);

2) glue a dedicated oil darkfield condenser to the adapter concentrically.

Resulting images are pretty good. Darkfield works up to 97x NA 1.25 oil objective stopped down with funnel stop (to NA around 0.8-0.85), or an iris immersion objective with NA set to NA 0.9.

I have also glued a NA 1.4 condenser, and used Lego spacers to make a filter slot right above the dovetail condenser adapter.

Forum member gekko has also done something similar to what I did, with his Optiphot's dovetail condenser mount.

Yes, Olympus BH2 has a very similar condenser mount.
I used that same dovetail adapter to add a dovetail to an earlier Olympus oil darkfield condenser (from BH maybe?). I took 1" PVC pipe and "turned it down" to the two dimensions I needed to couple the condenser to the adapter. Went together slicker than heck, and works perfectly on my BH2. I used a tablesaw to turn down the pipe to make the adapter, not a lathe.

Carl

Re: Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Thu Apr 14, 2016 9:04 pm
by zzffnn
If you don't mind the look, a few pieces of Lego's and a few drops of super glue is all that is required. Painted or black PVC would look better for sure.

Re: Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Thu Apr 14, 2016 11:06 pm
by billben74
Hello all this all sounds really interesting, any chance of any pictures of your lovely adpatations? (I realise carhl9062 has done this.)

Re: Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Fri Oct 13, 2017 11:27 pm
by Quarterbore
Moved to new thread

Re: Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Sun Apr 25, 2021 5:18 am
by qanunji
the link is dead.

Re: Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Mon May 10, 2021 2:49 am
by carlh6902
Updated link

Re: Adding Darkfield to Nikon Dovetail Conderser - Also of Interest to Oly BH2

Posted: Mon May 10, 2021 4:45 am
by linuxusr
Side question:

My new Zeiss scope has a dovetail ring at the base of the Abbe condenser. I see the dovetail ring indicated on my diagram but no function is mentioned in the manual . . . What is it?