Working in an "universal condenser" for Nikon Optiphot

[Jose Antonio Mena]

Hi

Last weeks I was working in a home made condenser for the Nikon Optiphot series.

The scope is to have free acces to the back focal plane of the condenser, in order to try differen ilumination tecniques: dark field, Reinberg, oblique, phase contrast, Pluta slit DIC condenser, and DIC condenser.

I am trying with a old Nikon SKE abbe condenser, without the iris diafragm; in that optics, the back focal plane is 6mm below the remain condenser.

In the desing, it´s posible to adjust a stage for put different slides,between 5 mm above the BFP, and 15 mm below the back focal plane.

Now I have to build different slides for different techniques.

Just now I haven´t done any test, but here are diferent pics of the work

Regards

fot1.jpg (52.69 KiB) Viewed 42589 times

[Jose Antonio Mena]

More pics

[Scarodactyl]

Looks like a cool project! I'll look forward to updates.

[Sure Squintsalot]

Hi

Last weeks I was working in a home made condenser for the Nikon Optiphot series.

The scope is to have free acces to the back focal plane of the condenser, in order to try differen ilumination tecniques: dark field, Reinberg, oblique, phase contrast, Pluta slit DIC condenser, and DIC condenser.

I am trying with a old Nikon SKE abbe condenser, without the iris diafragm; in that optics, the back focal plane is 6mm below the remain condenser.

In the desing, it´s posible to adjust a stage for put different slides,between 5 mm above the BFP, and 15 mm below the back focal plane.

Now I have to build different slides for different techniques.

I too have been thinking about this. How did you determine the back focal to be 6mm below the "remain condenser"?

....and any chance you know where it is on the flip-top Abbe condenser?

Excellent work, BTW!

[Jose Antonio Mena]

Hi
I understand, could be wrong, that the back focal plane is in the same position where was the diaphagm of the condenser that i dismount. It is built in a way that it is possible to change the position of a movile stage, that it is where you put different slides depending of the purpose.
The SKE conderser that I have used hasnt got flp flop lense....

[zzffnn]

Very cool project! I am following too.

Jose: You may want to paint your condenser parts with matte black paint. Eventually, a better corrected aplanatic or achromat condenser may work better.

Nikon Optiphot has lots of under stage space and is a good platform for condenser DIY. I have adapted a Leitz Heine, a Bausch & Lomb parabolic darkfield condenser to my Optiphot. They both work really well.

[Jose Antonio Mena]

Thanks; yes, I have to paint the areas exposed to light. Just now I have to meke the first test in order to check that all I put in the condenser stage is focused in the rear focal plane of the objective. I want to check the Pluta slit dic in a first aproach too.

[Jose Antonio Mena]

Hi all:

Afther several months, with several familiar duties, I have returned to the project.

Nice results.

First test with the Mathias arrow oblique ilumination and cheeck cells sample. Very nice view.

Second test: Pluta DIC system.

I have used a EPI-DIC nosepiece , four prisms (cheap, 200 Euros cost); Nikon CF plan 160mm 4X, 10X, 20X, 40X objectives with adaptors female RMS to 26mm male.

Yes, I know I´m working heterodox way with 160mm objectives in a system with aprox 175 mm tube legth....

I have done in black cardboard a sheet with a slit oriented 45º, and put it in the tray of my own made condenser.

A linear polarizer sheet below the condenser.

A Nikon micoscope linear POL analyzer over the microscope frame, and below the head.

Koeler ilumination adjust.

The conoscopic view is the slit of the cardboard with a black band that covers the central third of the slit along it; The legth of the slit is about the 3/4 of the diameter of the conoscopic view; The width of the slit must be adjusted for each objective..

Nikon optiphot 1 frame.

Good DIC view in the different magnifications of the cheeck cell sample and bacteria included (coco, bacillo, spirilium); I think that similar result the Nikon diascopic DIC system.

When I will have more time, more test

Best regards

Jose Antonio

[Jose Antonio Mena]

The EPI BD DIC nosepiece with the CF Nikon 160 objectives, and the analyzer

[Jose Antonio Mena]

The condenser, with the slide inside...

and, yes.... I´ve to paint in black the areas in the ligth way....

[Jose Antonio Mena]

The slide outside the condenser

[Jose Antonio Mena]

The slide: two aluminium frames with magnets for join, and the slit in cardboard for get Pluta DIC with the CF 40X 160mm objective and EPI BD DIC nosepiece

[Macro_Cosmos]

For DIC to work, you need to know the focal length of the condenser too, otherwise you are just gambling.

Ideally, you want the focal length to be the same as a proper universal condenser. This is totally doable but not trivial.

[Jose Antonio Mena]

Hi again:
Hi macrocosmos
I have tried the next arrange with good results.
The back focal plane of the condenser is determinated, about 6mm below the uper support of the optics (just the original position of the condenser iris).
I put the slider with the slit in that position.
I had to test diferent slit sizes for each DIC upper prism and objective for get good results.
In this DIC scheme you loos NA and resolution in one direction, orthogonal to the slit.
The advantage is that you can use the DIC prisms more freely, only have to match the size of the slit; PZO have a condenser for DIC with the same principle. Similar too that PlasDIC system from Zeiss (Similar, but not the same, Zeiss put the polarizer upside the condenser and preparation; in Pluta arrange, the polarizer is downside the condenser).
It allows me to use a epi-dic nosepice for trasmited ligth DIC.
All sugerences and ideas are wellcomed. I can be wrong, of course. Thanks.
Regards
JA

[Jose Antonio Mena]

I have few time now, but next will be try to work with DIC prisms in the condenser, and try to match them...
Just now changing the optics from Abbe to Achromatic condenser, and work in a gradient contrast slide for oblicue illumination...

[Sure Squintsalot]

...still following.


What is your plan for the condenser DIC Prism?

[Jose Antonio Mena]

Hi Squintsalot:

I startted to work whit a set of PZO DIC prism (one dude from Poland sell them "cheap") in a slider mechanizad for suport them; as with this condenser I can adjust them in the 3 axis and rotate, I hope I will get an match, but need time...

I will return with the experiences...

[Sure Squintsalot]

He sells them as "loose' pieces, correct?

I think he removes them from old PZO condensers. I have looked at those too.

[Jose Antonio Mena]

Yes he´s
I think he´s a former worker of PZO or technician, or so...
He sells different optical devices, quartz edges, etc, could be nice stuff for experiments.

[Jose Antonio Mena]

More about the slit condenser for DIC:

http://www.zebrasc.com/upimages/200912/ ... 132510.pdf

Remember, Zeiss is similar Pluta slit DIC, but not the same, Zeiss put the polarizer upside the condenser and preparation; in Pluta arrange, the polarizer is downside the condenser).

[Jose Antonio Mena]

and some about gradient contrast

https://www.olympus-lifescience.com/es/ ... -contrast/

[Jose Antonio Mena]

The suports for the DIC prisms in the condenser

[Jose Antonio Mena]

The filter for the variable obicue contrast (gradient contrast)

[Jose Antonio Mena]

The slits for the DIC (plasDIC or PZO slit DIC condenser principle)
Each one is for one objective NA band. Bigest one for use with the Nikon CF Plan 40X, smallest for the Nikon CF plan 5X; I haven´t tried with oil inmersion yet.

[Sure Squintsalot]

Screenshot 2023-11-29 101543.jpg (143.44 KiB) Viewed 40682 times

What you are doing suddenly comes into "focus"!

[Jose Antonio Mena]

yes, you can see it draws in the Zeiss paper. Slit width in function of interference fringe distance versus contrast, see fig 4, page 8.

Thanks Squint!

[Jose Antonio Mena]

This is the new version with the acromatic optic

[Jose Antonio Mena]

Whith the slit for DIC
The achromatic optic have the back focal plane 14mm from the flange, despite the 6mm in the Abbe optic...

[Jose Antonio Mena]

Now, it´s black painted in the light way...

[Jose Antonio Mena]

And last, the epi dic nikon BD nosepiece with the CF plan 160mm objectives, 4X, 10X, 20X and 40X; all them give DIC with the split slides...