Question about darkfield inmersion condenser

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einman
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Joined: Tue Feb 24, 2015 1:03 am

Re: Question about darkfield inmersion condenser

#31 Post by einman » Sun Jun 03, 2018 2:26 am

Image

clipi
Posts: 51
Joined: Sat May 19, 2018 11:13 am

Re: Question about darkfield inmersion condenser

#32 Post by clipi » Sun Jun 03, 2018 5:37 pm

Thanks Einman

I think i got it close enough to your measurements. The only thing left is the thickness of the slider
and the thickness of the depression where you place the annuli.

Now going back to the Darkfield condenser.. I recentrly viewed on youtube this video
https://www.youtube.com/watch?v=d6jsnLIsNwI
Around 10:39 he explains that to achive true Darkfield one need to reduce the Numerical aperture of the objective.
Either by way of a funnel or by and Iris below 1.25 is that correct?
I tough that if you have a 100x 1.25 lens and if you also have a 1.25-1.40 condenser that was not necesary.

My objective does not have a hole to slide in a funnel. It is a Leitz NPL Fluotar 100x 1.32
I might get this zeiss objective... do you think that will work on my Leitz Laborlux microscope? Is it good?
Thanks again for being so helpful.
Attachments
zeissobjective2.jpg
zeissobjective2.jpg (143.98 KiB) Viewed 6444 times
SliderMicroscopeCondenser.jpg
SliderMicroscopeCondenser.jpg (93.73 KiB) Viewed 6444 times

einman
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Joined: Tue Feb 24, 2015 1:03 am

Re: Question about darkfield inmersion condenser

#33 Post by einman » Mon Jun 04, 2018 2:01 am

Impressive. What software are you using for these images?

The objective should have an NA BELOW that of the condenser. If you have a 1.4 NA "darkfield" condenser than you should be able to use a 1.25 but 1.32 is probably pushing it. Recognize the closer the na of the objective to that of the condenser the increased potential for deterioration of the image.

When using stops such as in the Leitz series 56 condenser you generally can not use an objective with an na above 0.65 or 40X. Dedicated darkfield condensers work better at na's above 0.65.

According to Olympus the max na of an objectives using ANY dedicated Darkfield condenser should be 1.30. (https://www.olympus-lifescience.com/en/ ... darkfield/)
Last edited by einman on Tue Jun 05, 2018 1:17 am, edited 1 time in total.

clipi
Posts: 51
Joined: Sat May 19, 2018 11:13 am

Re: Question about darkfield inmersion condenser

#34 Post by clipi » Mon Jun 04, 2018 8:44 am

Hello Einman

I made it with Sketchup. There is a free version you could use here.
can you tell me the thickness of the slide so I adjust the model and share it?

https://www.sketchup.com/es/sketchup/20 ... en-x64-exe

I have a 1.25 condenser from Nikon microscope. I will test it out. But back to the "custom made Iris" you suggested for the objective...
If I undertood it correctly, I need to cut a black paper disc about the size of inner diaphragm (the ring with the notches) as seen on the picture?
Then make a hole of about 75% of the "lens" size right?... if neede make more disk with a larger or smaller hole.

I wonder if there are is a modern version of this adaptor iris from the past..

Thanks
Attachments
nosepiece.jpg
nosepiece.jpg (109.24 KiB) Viewed 6424 times
iris.jpg
iris.jpg (148.12 KiB) Viewed 6424 times

billbillt
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Joined: Mon Nov 10, 2014 10:01 pm

Re: Question about darkfield inmersion condenser

#35 Post by billbillt » Mon Jun 04, 2018 2:55 pm

Here is a link to a very powerful 2D Cad program for free.. I works almost identical to AutoCad... I like it..

https://www.3ds.com/products-services/d ... -download/

BillT

einman
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Joined: Tue Feb 24, 2015 1:03 am

Re: Question about darkfield inmersion condenser

#36 Post by einman » Tue Jun 05, 2018 1:20 am

The slide is 2.90 mm thick. I have an iris like the one you post pictures of. It was made by leitz and attached to their objectives.

clipi
Posts: 51
Joined: Sat May 19, 2018 11:13 am

Re: Question about darkfield inmersion condenser

#37 Post by clipi » Tue Jun 05, 2018 8:40 am

The ring idea look cool, too bad it is so hard to find!. Are they desgined for 170 mm lenses or 160 mm?
To bad there are no modern version on sale.

I have two more question that I hope you can answer.

1) The phaco lens are only intended for phase contrast or can be uses as regular brightfield lenses as well?
2) If one use a phaco 3 100x objective for phase contrast do I have to put inmersion oil in the condenser as well
as I would with Darkfield?

Thanks again!

einman
Posts: 1508
Joined: Tue Feb 24, 2015 1:03 am

Re: Question about darkfield inmersion condenser

#38 Post by einman » Tue Jun 05, 2018 2:42 pm

1.Phase contrast lenses can be used for brightfield. Theoretically you are supposed to have some deterioration in resolution although whether you can discern it is debatable.
2. The subject of oiling the condenser is covered in another thread quite extensively. For 1.25 Na objectives I do not oil the condenser although for higher na I do. Technically you do not get the full benefit of 1.25 na if you do not oil the condenser. You might want to review the threads on oiling the condenser etc here on the forum. It gets quite involved.

Gasman
Posts: 153
Joined: Sat Jan 09, 2016 1:36 pm
Location: North East UK

Re: Question about darkfield inmersion condenser

#39 Post by Gasman » Wed Jul 15, 2020 7:15 am

Hi guys
I have a Laborlux S and recently bought a 56 condenser to try darkfield and Rheinberg illumination and pleased I found this post as I have been struggling to find any info on dimensions for the slider. I plan to buy a 3d printer soon (still deciding which one to get,!) and it would be brilliant if anyone has printed these and could post the stl files to help with learning the 3d software. Indeed any stl files used to enhance the scopes would be very helpful if poss please!! 👍
Thanks
Steve

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