Darkfield Cardioid Immersion Condenser NA 1.05

By Dushan Grujich, on January 28th. 2014


About a year ago, I have acquired a NOS Zeiss Cardioid DF condenser NA 1.05. It came equipped with 39.5 mm mount, which does not fit any of my 'scopes, so condenser just got pushed to the back of a shelf awaiting for a moment of my free time to do something about it. 

With Zeiss Nf stand having identical condenser on the revolving turret as part of the Pancratic Condenser System, and Reichert DF condenser already in use on one of LOMO Biolam 70 'scopes, Zeiss Cardioid DF condenser was almost forgotten about.




Couple of weeks ago I purchased a lot, consisting of various Leitz microscope components, among many goodies there was centreable condenser carrier mounted on dovetail slider used with Leitz DF № 82 and № 84 condensers, and of course, condenser was missing.


This prompted me to do something about it, I recalled that I already have an unused DF cardioid condenser which allows condenser cell to be easily removed from its mount, screwed in by standard RMS thread.

All that needed to be done was a mounting piece to place condenser cell at the correct height in the Leitz carrier in order to be able to slide in the DF condenser without need for readjustment of object stage in order to prevent condenser touching slide bottom side. Both, Leitz condenser carrier and Zeiss condenser cell were conveniently threaded with the RMS thread 0.800" 36 TPI. Thus I turned an adapter in lathe, from thick wall extruded aluminium pipe with OD 25.0 and ID 17.0 mm, the necessary height proved to be exactly 20.0 mm, a male RMS thread on one end, and female on the other. Finished adapter is shown at the image below.

Bottom end was screwed into the Leitz condenser carrier, and into its top end the Zeiss DF cardioid condenser cell was screwed in. Thus, I ended up with a perfectly usable Cardioid DF condenser.

The result can be seen below, an image of Pleurosigma Angulatum, part of the 8 Form Test Plate by Klaus D Kemp, taken with Leitz achromatic objective P 50/0.85 170/0.17 using Leitz Laborlux-Pol microscope and a simple CMOS sensor 1.3 Mp digital eyepiece camera without relay lens, plugged directly into the tubus. Image is single shot, and it has not been post processed, it was only reduced in size to 800 x 600 pixels.