DIC question

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iwamori
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DIC question

Post by iwamori »

I just bought an old Olympus vanox-t AH-2 scope. It came with a few items I think are for DIC but am not sure. I was wondering if anyone could shed some light on what these are. On a related note, if anyone has DIC setup for their AH-2 I'd love to know how its done.

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Last edited by iwamori on Mon Oct 08, 2012 10:01 am, edited 1 time in total.

Pau
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Post by Pau »

I don't know this model and its equipment, but I guess:
#1 and #2 seem analyzers (the polarizer that sits between the objective and the microscope head)
#3 seems another polarizer
#4 may be a set of Nomarski DIC prisms (or phase rings) because it has positions for different magnifications

You can test is properties playing with them in front of a light source:
- two linear polarizers will extint the light when its optical directions are crossed.
- Circular polarizers will do the same in one side, avoiding extintion the other side
- a DIC prism placed between two crossed polarizers will show parallel and symmetric colored bands like:
http://www.olympusmicro.com/primer/tech ... intro.html , fig 7

but none of them look like the ones pictured in the vanox brochure
http://www.alanwood.net/downloads/olymp ... ochure.pdf , p. 8
Pau

iwamori
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Post by iwamori »

Thank you Pau, I will track down some polarizers to work out what #3 and #4 are. I've looked at essentially all the olympus manuals/brochures from the Alan Wood site, unfortunately none identify exactly what I have. I'd like to do DIC but I'm not sure if the components I have are all that is necessary.

Pau
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Post by Pau »

Another important point is where do the sliders fit in your microscope, in the microscope head/intermediate tube or in the condenser.
iwamori wrote:...I will track down some polarizers to work out what #3 and #4 are.
I think you already have two good polarizers: 3 and 2 or 1 (or both)

Does any of these sliders have a rotatable knob to adjust linear translation?
I ask it because it is a typical feature of Olympus DIC objective prisms.
Pau

iwamori
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Post by iwamori »

#3 with #4 produced the rainbow effect if held one way, and can extinguish light if held a different way. Same for #3 with #2
#3 with #1 only extinguishes light

#1 acts like #3 can produce rainbow or extinguish light when paired with #4 and #2.

#2 has a rotatable nob.


So from what you said, looks like #3 and #1 are polarizers and #2 and #4 are nomarski prisms. Strangely enough, if i hold #2 or #4 in front of my lcd computer screen, I see the rainbows effect. A nice reminder that lcd's produce polarized light. I tried looking at some nissl stained rat brain sections, pairing the prisms with the polarizers, which resulted in a minor effect on the color. It did not look like a stereotypical DIC brain coronal section:

http://www.invitrogen.com/site/us/en/ho ... .2641.html.

Maybe I am missing some other needed component.

Pau
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Post by Pau »

iwamori wrote:#3 with #4 produced the rainbow effect if held one way, and can extinguish light if held a different way. Same for #3 with #2
#3 with #1 only extinguishes light

#1 acts like #3 can produce rainbow or extinguish light when paired with #4 and #2.

#2 has a rotatable nob.

So from what you said, looks like #3 and #1 are polarizers and #2 and #4 are nomarski prisms.
So I think that the Nomarski prisms 2 and 4 have built in polarizers, so when correclty placed, don't need the other polarizers, that will be intended for simple polarizing work.

If #4 fits the condenser slot like #3, you may have the complete setup:

#2 in the microscope head or nosepiece slot (objective prism + analyzer) and #4 in the condenser slot (polarizer + condenser prisms, one for each manification 10, 20, 40 and 100 and extra positions por BF and pol)

Be aware that fine tuning a DIC microscope isn't trivial. You must use the adequate objectives (not obvius if they aren't sold toghether), careful set the polarizers to extintion, and to set up the illumination to Kölher and the adequate condenser prism for each objective and of course regulate the objective prism translation to obtain the optimum shear to get good contrast.

Clear pictures of the microscope showing the slots where the DIC sliders fit would help to understand your fairly unusual microscope and may be to provide further advice.
Pau

iwamori
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Post by iwamori »

Thank you for your help. As you guessed, #2 does fit above the objective and #4 fits in the condenser slot. I don't really know what kind of objectives are needed; I have S plan apo 4x,10x,20x and 40x objectives. I'll post some pictures of the setup when I have a chance.

Pau
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Post by Pau »

iwamori wrote: I have S plan apo 4x,10x,20x and 40x objectives.
If they work with your DIC components they are the best ones.
Charles Krebs use these with his BH for DIC with wonderful results.
Pau

iwamori
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Post by iwamori »

After spending more time fiddling with the prism nob and getting the right prism below the condenser, I was able to get it to work! Now I just need to find an old smart card so I can post some pictures.
I was able to look at rat brain sections stained in multiple ways (golgi, nissl, dab, vector red) and none seem to provide really high contrast, so either I may still have some tinkering to do or DIC just isn't an ideal way to visualize brain sections. If someone can prove me otherwise I'd love to see some great pictures. Thanks for all your help. :D

Pau
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Post by Pau »

You're wellcome.:D
Please don't forget posting pictures of the microscope and of the brain section slides.
DIC may not be the best technique for fixed histological sections but can complement stain techniques.
To test your setup you can beguin with water mouted slides (buccal mucose cells, blood, pond water life...)
Pau

Cactusdave
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Post by Cactusdave »

I have taken pictures of mounted brain sections stained by the methods of Golgi and Cahal. These are commercial slides produced for medical and veterinary students. I don't think with this type of stained slide DIC necessarily contributes very much to the detail visible over carefully set up normal transmitted light. There are other instances where DIC does work well with histological sections, especially unstained sections. Unstained histological sections were sometimes sold by the Victorian mounters as subjects for polarised light, and such slides can provide good material for DIC as well as the originally intended polarised light.

If you like I can post one or two of my pictures for illustration.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

iwamori
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Post by iwamori »

As promised here a few pictures illustrating the AH-2 DIC configuration, at least with the components I have.

Notice the analyzer/prism insert above the objective nose-piece. There's also another slot above it that remains a mystery to me. None of the filters or polarizers I have fit, any ideas would be appreciated:

Image

And here's the prism/polarizer slotted below the condenser:

Image

So that's the complete AH-2 DIC setup.

If anyone has a different AH-2 or AH-3 DIC setup I'd love to see it, there isn't a lot of information out there regarding the various modules made for this scope and this seems as good a place as any to have this information available to people.

Pau: I tried some unstained cheek cells and they looked great with DIC, unfortunately I'm still trying to get my camera setup working so that I can share.

Cactusdave: I'd love to see some of your pictures.

Cactusdave
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Post by Cactusdave »

That's a very fine microscope. I hope that's not a leaky window right behind it though :). Damp is really bad for high quality optics and in the worse case can lead to growth of fungus on optical surfaces. :( Be warned.

I will post some of my pictures of histological type subjects in the 'photography through the microscope section' shortly. I'd like to take a few more brightfield shots of the Cahal and Golgi stained sections for comparison with DIC first.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

iwamori
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Post by iwamori »

Thanks for the tip, I'm in the process of making a better space.

NicoVB
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Post by NicoVB »

Rather old thread, but nobody really gave the answer.
The solution is easy,

1 and 3 is a polarization set
2 and 4 the DIC set like displayed below
Image
When you make the most fantastic discovery, a lot of people want a piece of it...

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