My problem with DIC PZO

[microplan]

Hello
I have been the owner of DIC PZO for a long time
But it was only two days ago that I connected it to the microscope.
I don't have the original PZO microscope, so I installed it in the CZJ Fluoval body.
To do this, I used my various "patents and inventions"
Despite initial difficulties, I put it together.
My problem is that I can't get a soft and uniform background.
I will show it in the attached photos:
1. Crossed polarizers.
The lever on the upper head is in position 0.
Condenser disc position 0
2. Crossed polarizers.
Lever on the upper head, position 1.
Condenser disc position 0
3. Condenser disc, position 10
4. Condenser disc, position 20
5. Condenser disc, position 40
6. Condenser disc, position 100
Lens: Nikon Plan20/0.40 DIC
Adjustment using the side knob and the huge ring on the upper head did not help much.
Maybe I'm making a mistake or it's a feature of DIC PZO.
Thank you in advance for any advice.
I use an online translator, so maybe not everything will be understandable.

Regards
Maciej

[mazdowiecki]

Why not join and open a discussion here https://www.facebook.com/groups/mikroskopiaamatorska ? There are a few experienced PZO DIC users there (unfortunately, not me :/ ) who might want to help you.

Regards
Karol

[Scarodactyl]

Is the nikon objective known to be compatible with this system? Not every objective will work, it's actually unusual to have cross compatibility.

[JWW]

I agree with Scarodactyl. Try another objective.

[deBult]

If memory serves me: I think PZO has a series of specific DIC objectives.

[apochronaut]

Yes, they did. However, the system used an understage polarized slit condenser, a carousel polarized 4 prism condenser, 4 objectives with built in rotating prisms and an interference head with polarized focusing prisms in a kind of mix and match technique arsenal. Quite complicated really because there were 5 combinations of those components to produce 5 individual interference contrast techniques. I think 3 of those techniques used plain planachro objectives but obviously strain free types. The interference contrast objectives, the ones with the integrated prisms were used for only 2 of the 5 interference techniques described in the manual.

[PeteM]

Ideally, you end up with the upper prisms at the back focal plane of whatever objectives you find.

In addition to Stephen's point about objective compatibility, you may want to be mindful that your adaptation of the PZO upper DIC prisms ends up at the same height above the objective as on a PZO system -- and ideally has some adjustment. I recall having to fuss with the upper PZO prism head fitting to an Olympus BHT, getting it closer to the objective, to get good DIC images. You want a 160mm tube length when you're done - but a good starting point is to have the prisms sitting within that tube length at near the same height as they would be in a PZO system.

[apochronaut]

Your background lack of uniformity makes it seem that your prisms are out of alignment. It is oddly blurry too but that could be an artifact of prism misalignment.

Sometimes the PZO compensator prisms have been messed with and adjusted from their factory settings .Assuming that both polarizers are good, since the upper one in particular is prone to de-lamination over time, and the compensating lenses in the top and bottom of the interference head are both intact and good and your objective is 160/.17 , here is the prescribed method for operating the system. After I key this all in I will check the measurements on a Biolar, so you can check your system for gross vertical meaurement errors. As Pete suggested, perhaps your upper compensating prisms are too high and you can't adjust the interference head on it's helical X path any lower than bottom, so if your system is too tall, you may have to either find a way of trimming a collar, dovetail or something or look towards fitting the system on another stand. I would recommend a Biolar. They are cheap, sturdy, handsome, have interchangeable nosepieces and a 5 position nosepiece is available cheap too. I bought 3 of them for under 100.00. There isn't a lot not to like about them.

Put a slide and coverslip on the stage and move it until a clear section is being viewed. move your chosen 20X objective into place.
Make sure the condenser is centered using the open port. Set the analyzer to 45 and the polarizer to 45 or 135.
The illumination system must be adjusted for Köhler. Won't work otherwise. Once adjusted , for a 20X objective choose the compensating prism marked 20. Observe the exit pupil of the objective through a bertrand lens or centering telescope and using the micrometer knob on the side of the prism housing adjust it to get the first interference order colour purple. The image of the lamp filament through the centering telescope should be a solid purple. If it is not solid purple, the condenser prism has been messed with and altered from the factory settings. It must be rotated one way or the other to achieve a solid purple colour of the lamp filament. The prism is adjusted using a special key that fits into the adjustment hole.Once properly adjusted for rotary alignment, the prism need not be adjusted again as long as the condenser housing is in it's correct position. Once the uniform colour condition of purple has been met through the telescope eyepiece, when the visual eyepiece is installed, it should also have a uniform purple field. If it is different, adjust the interference head up or down until it is Sometimes when adjusting the large knurled ring, the purple colour might fade. Adjusting the lateral micrometer screw will reestablish the purple intensity. Sometimes the lamp filament focus and alignment will need tweaking in order to get a uniform field. A dispersion filter or ground glass can be used, if for some reason a lack of uniformity is persistent. This completes the prism adjustment and the same procedure is required for each objective used.
Once a uniform field has been established , the birefringent prism in the interference head can be adjusted to achieve a uniform field in any other interference colour, as well as a grey background.

[apochronaut]

Your background lack of uniformity makes it seem that your prisms are out of alignment. It is oddly blurry too but that could be an artifact of prism misalignment.

Sometimes the PZO compensator prisms have been messed with and adjusted from their factory settings .Assuming that both polarizers are good, since the upper one in particular is prone to de-lamination over time, and the compensating lenses in the top and bottom of the interference head are both intact and good and your objective is 160/.17 , here is the prescribed method for operating the system. After I key this all in I will check the measurements on a Biolar, so you can check your system for gross vertical meaurement errors. As Pete suggested, perhaps your upper compensating prisms are too high and you can't adjust the interference head on it's helical X path any lower than bottom, so if your system is too tall, you may have to either find a way of trimming a collar, dovetail or something or look towards fitting the system on another stand. I would recommend a Biolar. They are cheap, sturdy, handsome, have interchangeable nosepieces and a 5 position nosepiece is available cheap too. I bought 3 of them for under 100.00. There isn't a lot not to like about them.

Put a slide and coverslip on the stage and move it until a clear section is being viewed. move your chosen 20X objective into place.
Make sure the condenser is centered using the open port. Set the analyzer to 45 and the polarizer to 45 or 135.
The illumination system must be adjusted for Köhler. Won't work otherwise. Once adjusted , for a 20X objective choose the compensating prism marked 20. Observe the exit pupil of the objective through a bertrand lens or centering telescope and using the micrometer knob on the side of the prism housing adjust it to get the first interference order colour purple. The image of the lamp filament through the centering telescope should be a solid purple. If it is not solid purple, the condenser prism has bern messed with and altered from the factory settings. It must be rotated one way or the other to achieve a solid purple colour of the lamp filament. The prism is adjusted using a special key that fits into the adjustment hole.Once properly adjusted for rotary alignment, the prism need not be adjusted again as long as the condenser housing is in it's correct position. Once the uniform colour condition of purple has been met through the telescope eyepiece, when the visual eyepiece is installed, it should also have a uniform purple field. If it is different, adjust the interference head up or down until it is Sometimes when adjusting the large knurled ring, the purple colour might fade. Adjusting the lateral micrometer screw will reestablish the purple intensity. Sometimes the lamp filament focus and alignment will need tweaking in order to get a uniform field. A dispersion filter or ground glass can br used, if for some reason a lack of unuformity is persistent. This completes the prism adjustment and the same procedure is required for each objective used.
Once a uniform field has been established , the birefringent prism in the interference head can be adjusted to achieve a uniform field in any other interference colour, as well as a grey background.

I measured the vertical height. Since I don't know where the back focal plane of the Nikon objective you are using is, I measured from the nosepiece objective mating surface to the interference head mating surface. It's 52mm.
With regards to the adjustment key referenced above. PZO took pains to make it hard for your spouse or neigbour to put your prisms out of adjustment out of sheer spite.Sheer spite is much worse than just spite, similar to sheer Hell. Much worse. The key comes in the Interference Contrast kit and is a specialized kind of claw that drives a lateral pin . Basically a small reversed slot screwdriver with the slot in the driver. The shaft is 52mm long, 3mm in diameter. The claw gap is 1.5mm wide.
Just in case you don't have one.

[microplan]

Hello everyone.
And thank you all very much for your kind willingness to help me.

Karol - thanks for the idea to post the problem on Facebook. It will undoubtedly be more convenient for me to use my native language

Scarodaktyl - thank you for the suggestion regarding lenses. My DIC PZO set includes the MPI-5 head, which is apparently quite universal and compatible with various lenses.

JWW - I checked with other lenses.
These were: NPL FLUOTAR 10/0.30
Nikon Plan 20/0.40 DIC
Nikon PlanApo 40/0.95
NPL FLUOTAR 100/1.32

deBult - you are certainly right, but I do not have the PZO lenses you are thinking about.
I have PZO PI lenses with a red stripe, but they produce a very split image that is used for other purposes.

PeteM - because I knew that PZO produced microscopes with a tube length of 160, and my Fluoval also has this length, so I thought there would be no problems. Initially, I placed the camera on the light port of the upper head, but then there was a lot of black around the resulting image. To avoid this, I raised the camera up. The black is gone, but I'm afraid I won't be able to keep the condition you mentioned.

apochronaut - Your answer is a real, extremely professional lecture. You have brought to my attention so many things that I will have to spend a lot of time getting to know them. These are details about both theory and practice. I have to get through this. And you described it step by step. Thank you.
My PZO DIC system is quite complete including adjustment keys. While rotating the prisms in the condenser with a key, I observed the image, but did not see any change. I don't know if that's good or bad.
Finally, I have to admit something.
My microscope was a Fluoval in which I used overhead lighting. Only now have you made me realize that I need Kohler lighting and I didn't take care of it.
So I have to recreate this system that I neglected. And here I have a question: can I use an LED for this purpose or does it have to be halogen?
When I deal with it, I will let you know on the forum because there will certainly be new questions.

Thank you again and best regards.

Maciej

[apochronaut]

I think the Köhler condition is necessary to produce an even source of light but also to image the filament in the centering teiescope in order to achieve the first order purple colour.. If you can provide an even light with led that would also work but since the wavelengths of led are different than those of halogen, it may be difficult to acertain the cemtering and intensity levels.

However , am I correct in understanding that you used EPI lighting?

[microplan]

Hello apochronaut.

I'm already answering your question.
In this particular case, I did not use EPI lighting.
I only wrote that my old Fluoval has two types of lighting: DIA and EPI.
So far, I have only used EPI illumination for observations in reflected light (autofluorescence).
I used the remaining transmitted light techniques on another microscope.
But it is corrected to infinity, so it is not suitable for DIC PZO.
Fluoval has a tube length of 160 and fits DIC PZO.
But it also has a neglected lower lighting path that has not been serviced by me, and maybe that is why the lighting does not meet the appropriate conditions.
As I promised, I installed a strong diode as a light source, but the image has a strong green tint and is simply ugly.
I will have to use a halogen lamp in the second attempt, but it will take some time.
I have disassembled the DIC head and in my opinion all optical components are in excellent condition.
Mechanically too - the ring, knob and lever everything moves without any problems.
The condenser is also good.
I wonder what could be wrong with my set.
Interference stripes appear and move, there is only no relief effect, and when rotating the crystals in the condenser, no effects could be observed in the image.
Maybe you can tell me what I should expect.
For now, I do not think that the set may be damaged in any other way, even though I bought it second-hand.
I also have no way to check it on another microscope.
It looks like it will take me a few days to form an opinion on it.
Thank you for your solid advice and whenever I achieve even small successes in solving problems, I will boast about them.
Or I'll keep asking for help.

For now, best regards
Maciej

[apochronaut]

Going back to Pete M's comment that he had to lower a PZO interference head when adapting it to an Olympus BHT, check the nosepiece face/objective shoulder to the interference head dovetail surface. I get 52mm on a Biolar. You wouldn't want to be taller than that, I would think.

[microplan]

To be honest, I don't really understand what it means to lower the position of the interference head. My head rests on the port to which I connect the eyepiece and I view the image on the camera screen. Physically, I can't lower the head position any further or I don't understand something when it comes to the translation into Polish. Maybe you have a link that would show the measurements in the drawing. I have another 160 microscope. It is an old and heavy Russian BIOLAM LIUMAM. I connected my DIC system to it, but the final image I received was also terrible. I'm starting to suspect that my DIC is faulty, but I decided to do one more desperate test.
It looks like:
I'm holding an MPI 5 head in my hand.
I look through the head at the glowing monitor screen.
The working screen is a source of polarized light.
In the head, the analyzer is set to 45 and the lever with the crystals is in position 1.
I see beautiful, clear and very clean stripes in my field of vision. By moving the analyzer back and forth, the bands blur and reappear.
The movement of the micrometer knob causes the bands to move back and forth.
Therefore, I conclude (maybe too hastily) that the head is in good condition.
However, I have no idea how to easily check the technical condition of the condenser without mounting it on a microscope. Maybe I'll think of something by the evening. If I find time, I will take photos of my configuration in the evening and maybe then we will determine what dimensions and measurements are involved.

Regards

[apochronaut]

Since the distance used on the Biolar is 52mm, then if you can't lower the interference head on your microscope to that height above the nosepiece facing surface, it is possible that is the problem with the system. I don't know how to lower it on your microscope. It may be easiest to look for another inexpensive stand in order to get Interference Contrast to work.

[microplan]

Hello

After a long break, I decided to refresh this thread.
I thought that I owed it to all forum members who gave me advice and tips on how to solve my problem related to PZO DIC.
In particular, I would like to thank forum member "apochronaut". Your comments were very useful and even inspiring for me. I will definitely follow them when configuring and arranging the equipment and lighting.
But to the point. I must admit that I completely lost trying to fit my PZO DIC to other microscopes. The results obtained were pathetic.
Even connection with older PZO microscopes did not give interesting results. I finally came into possession of a Biolar PZO microscope. And it turned out that everything was in its place and everything fit.
The attached pictures show my set. I will take photos with a camera placed on the connector instead of a head with glasses.
The last two pictures are photos taken quickly without precise positioning of polarizers, prisms and lighting.
I will explore this topic further.
Thank you all very much again.

Regards
Maciej