Aplanatic-Achromatic Condenser Design?

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LouiseScot
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Aplanatic-Achromatic Condenser Design?

#1 Post by LouiseScot » Wed Sep 22, 2021 3:07 pm

Hi all

I've been searching everywhere trying to find details describing the practical design of a high quality substage condenser. I suppose actual commercial condensers come under the purview of intellectual property but I have an instinctive feeling that there could/should be some practical guidance out there somewhere. If anyone has any links to books/documents/published papers that would be great!

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#2 Post by BramHuntingNematodes » Wed Sep 22, 2021 3:13 pm

They are big achromat objectives.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

apochronaut
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Re: Aplanatic-Achromatic Condenser Design?

#3 Post by apochronaut » Wed Sep 22, 2021 3:27 pm

Look up patents. There are reams of them.

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#4 Post by LouiseScot » Wed Sep 22, 2021 4:17 pm

apochronaut wrote:
Wed Sep 22, 2021 3:27 pm
Look up patents. There are reams of them.
Hmm... the ones I've seen lack practical detail. Maybe I'm hoping for too much and just have to try things out for myself.
By the way, Do you know how to measure/gauge Numerical Aperture? That's something that's always puzzled me with compound lenses.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#5 Post by BramHuntingNematodes » Wed Sep 22, 2021 4:28 pm

you should be able to measure it directly by shining a bright light through and have it project on to a card on end
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

apochronaut
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Re: Aplanatic-Achromatic Condenser Design?

#6 Post by apochronaut » Wed Sep 22, 2021 4:42 pm

LouiseScot wrote:
Wed Sep 22, 2021 4:17 pm
apochronaut wrote:
Wed Sep 22, 2021 3:27 pm
Look up patents. There are reams of them.
Hmm... the ones I've seen lack practical detail. Maybe I'm hoping for too much and just have to try things out for myself.
By the way, Do you know how to measure/gauge Numerical Aperture? That's something that's always puzzled me with compound lenses.

Louise
Probably there are those published that don't include all the details but there are also many that are quite complete. Right down to the glass indices used and their dimensions. Or do you mean where the focal points and planes lie etc.?
Here is one I trotted out in an earlier thread designed by George Aklin and Richard Seidenberg for Bausch& Lomb.
https://patents.google.com/patent/US3743386A/en
Last edited by apochronaut on Wed Sep 22, 2021 6:21 pm, edited 1 time in total.

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#7 Post by LouiseScot » Wed Sep 22, 2021 5:09 pm

apochronaut wrote:
Wed Sep 22, 2021 4:42 pm
LouiseScot wrote:
Wed Sep 22, 2021 4:17 pm
apochronaut wrote:
Wed Sep 22, 2021 3:27 pm
Look up patents. There are reams of them.
Hmm... the ones I've seen lack practical detail. Maybe I'm hoping for too much and just have to try things out for myself.
By the way, Do you know how to measure/gauge Numerical Aperture? That's something that's always puzzled me with compound lenses.

Louise
Probably there are those published that don't include all the details but there are also many that are quite complete. Right down to the glass indices used and their dimensions. Or do you mean where the focal points and planes lie etc.?
Here is one I trotted out in an earlier thread designed by George Aklin and Richard Seidenbrrg for Bausch& Lomb.
https://patents.google.com/patent/US3743386A/en
That seems to be a Leica one? It obviously uses bespoke lenses and those patent details aren't easy (for me) to follow. I had a bee in my bonnet re making one from off the shelf lenses... I was hoping to find something with some description of it's working. I'll have a play when my lens order arrives :)
Cheers
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#8 Post by LouiseScot » Wed Sep 22, 2021 5:11 pm

BramHuntingNematodes wrote:
Wed Sep 22, 2021 4:28 pm
you should be able to measure it directly by shining a bright light through and have it project on to a card on end
And?

Are there some details somewhere?

Thanks

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#9 Post by BramHuntingNematodes » Wed Sep 22, 2021 5:24 pm

trace the cone of light, find the angle using some such as a protractor, divide the angle by two and take the sin of it. That's it.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

BramHuntingNematodes
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Re: Aplanatic-Achromatic Condenser Design?

#10 Post by BramHuntingNematodes » Wed Sep 22, 2021 5:30 pm

also you prob figured this out but for high NA you will be measuring the cone post focal point with the card as close to bisecting the cone as possible.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#11 Post by LouiseScot » Wed Sep 22, 2021 5:37 pm

BramHuntingNematodes wrote:
Wed Sep 22, 2021 5:30 pm
also you prob figured this out but for high NA you will be measuring the cone post focal point with the card as close to bisecting the cone as possible.
I hadn't... Can you point me to a reference?

Thanks

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#12 Post by BramHuntingNematodes » Wed Sep 22, 2021 5:40 pm

I mean uh I guess there is always old microscopy u https://www.microscopyu.com/microscopy- ... l-aperture easiest way to get a feel for what the are talking about is to get a 10x and a 20x objective and a flashlight and start playing around.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#13 Post by LouiseScot » Wed Sep 22, 2021 5:51 pm

BramHuntingNematodes wrote:
Wed Sep 22, 2021 5:40 pm
I mean uh I guess there is always old microscopy u https://www.microscopyu.com/microscopy- ... l-aperture easiest way to get a feel for what the are talking about is to get a 10x and a 20x objective and a flashlight and start playing around.
That's useful - thanks!
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#14 Post by LouiseScot » Wed Sep 22, 2021 6:03 pm

BramHuntingNematodes wrote:
Wed Sep 22, 2021 5:40 pm
I mean uh I guess there is always old microscopy u https://www.microscopyu.com/microscopy- ... l-aperture easiest way to get a feel for what the are talking about is to get a 10x and a 20x objective and a flashlight and start playing around.
ps I think I would have to try and measure the diameter of the light cone some distance away, then measure that distance and compute the half angle.
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

apochronaut
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Re: Aplanatic-Achromatic Condenser Design?

#15 Post by apochronaut » Wed Sep 22, 2021 7:33 pm

LouiseScot wrote:
Wed Sep 22, 2021 5:09 pm
apochronaut wrote:
Wed Sep 22, 2021 4:42 pm
LouiseScot wrote:
Wed Sep 22, 2021 4:17 pm


Hmm... the ones I've seen lack practical detail. Maybe I'm hoping for too much and just have to try things out for myself.
By the way, Do you know how to measure/gauge Numerical Aperture? That's something that's always puzzled me with compound lenses.

Louise
Probably there are those published that don't include all the details but there are also many that are quite complete. Right down to the glass indices used and their dimensions. Or do you mean where the focal points and planes lie etc.?
Here is one I trotted out in an earlier thread designed by George Aklin and Richard Seidenbrrg for Bausch& Lomb.
https://patents.google.com/patent/US3743386A/en
That seems to be a Leica one? It obviously uses bespoke lenses and those patent details aren't easy (for me) to follow. I had a bee in my bonnet re making one from off the shelf lenses... I was hoping to find something with some description of it's working. I'll have a play when my lens order arrives :)
Cheers
Louise
No. It is Bausch & Lomb. Leica was the current assignee at the time that was printed because the company inherited it. Bausch & Lomb was part of the grand 8 company merger that spawned Leica , so all intellectual property would have been pooled. The merged company entered into a market frenzy in the early 90's which was essentially a scramble to get infinity corrected product on the market. They really only had Reichert and AO products in the stable that met the criteria, so much effort was put into expanding those optical systems into newer stands. The Bausch & Lomb modified infinity system was not really needed despite it's many intrinsic qualities, so the production was cancelled along with the obsolete 160mm tube designs of E.Leitz Wetzlar and Wild Heerbrugg. Patents were allowed to lapse. That's why some very interesting designs can be found on google.
Is this condenser to be fitted into a stand or will it be part of a d.i.y optical train? There are some surplus 1.4 N.A. back lenses available. The back lens determines the condenser's N.A. High N.A. plano convex lenses like that, which are oil sealed are not a common thing.

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#16 Post by LouiseScot » Wed Sep 22, 2021 7:47 pm

apochronaut wrote:
Wed Sep 22, 2021 7:33 pm
LouiseScot wrote:
Wed Sep 22, 2021 5:09 pm
apochronaut wrote:
Wed Sep 22, 2021 4:42 pm

Probably there are those published that don't include all the details but there are also many that are quite complete. Right down to the glass indices used and their dimensions. Or do you mean where the focal points and planes lie etc.?
Here is one I trotted out in an earlier thread designed by George Aklin and Richard Seidenbrrg for Bausch& Lomb.
https://patents.google.com/patent/US3743386A/en
That seems to be a Leica one? It obviously uses bespoke lenses and those patent details aren't easy (for me) to follow. I had a bee in my bonnet re making one from off the shelf lenses... I was hoping to find something with some description of it's working. I'll have a play when my lens order arrives :)
Cheers
Louise
No. It is Bausch & Lomb. Leica was the current assignee at the time that was printed because the company inherited it. Bausch & Lomb was part of the grand 8 company merger that spawned Leica , so all intellectual property would have been pooled. The merged company entered into a market frenzy in the early 90's which was essentially a scramble to get infinity corrected product on the market. They really only had Reichert and AO products in the stable that met the criteria, so much effort was put into expanding those optical systems into newer stands. The Bausch & Lomb modified infinity system was not really needed despite it's many intrinsic qualities, so the production was cancelled along with the obsolete 160mm tube designs of E.Leitz Wetzlar and Wild Heerbrugg. Patents were allowed to lapse. That's why some very interesting designs can be found on google.
Is this condenser to be fitted into a stand or will it be part of a d.i.y optical train? There are some surplus 1.4 N.A. back lenses available. The back lens determines the condenser's N.A. High N.A. plano convex lenses like that, which are oil sealed are not a common thing.
Hi
Well I was thinking about my diy dic which is just an optical train at the moment. I suppose a proper universal/dic condenser would be best but they are expensive. Also difficult to incorporate as things stand. When you say 'back' lens do you mean the 'bottom' in terms of a usual substage condenser? Naturally, I've set up an illumination system which incorporates Kohler.
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#17 Post by MichaelG. » Wed Sep 22, 2021 9:17 pm

This one is relatively simple in design, and the optical formula is fully disclosed:
https://worldwide.espacenet.com/patent/ ... US4060306A

But I doubt you will find suitable elements on-the-shelf anywhere. :(

MichaelG.
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Re: Aplanatic-Achromatic Condenser Design?

#18 Post by apochronaut » Wed Sep 22, 2021 9:20 pm

Back lens in the case of a condenser is the exit lens . It's usually a rather severe plano/convex lens of variable diameter, sometimes a doublet. The more severe the curvature of the leading surface, the higher the N.A. and of course any of them with an N.A. over 1.0 must be immersed to achieve that.
I built two condensers about 4 or 5 years ago using a factory condenser housing that was carrying an oil immersion back lens and had been ground to achieve a 1.4 N.A. spec.as marked on the upper shroud. The missing lenses would have completed a 1.4 N.A. oil immersion achromat/aplanat. Those blanks are still available. The surplus dealer that has them must have acquired quite a few of them. It's a pretty good blank to work with because the diaphragm housing that carries it, is one of the cheapest commonly available dovetail condenser/diaphragm frames available.
Originally, I was trying to make an oil achromat and an oil apochromat, using a triplet as a front lens. Neither ended up as great oil immersion condensers but one is a very good dry achromat, probably .95 or better. It produces a very bright even illumination. Superior to the factory made .90 achromat/aplanat.
The one with the apochromat front lens turned out to neither be a great dry condenser nor oil condenser. It is well corrected though and seems best suited to water immersion. I haven't evaluated it with glycerin. At this point intuitively, I tend to use the d.i.y. dry condenser usually and next the factory made 1.25 N.A. W.F. abbe aspheric if I want to oil immerse an objective. If the immersed objective is over 1.30 I use the factory 1.4 N.A. achromat/aplanat, which I acquired about 2 or 3 months after my d.i.y. project.z
Michael G posted that Krishnaiyer Swaminaithan designed condenser patent, while I was tapping away. That is the 1.3 N.A. version of the 1.4 N.A. condenser that I mention above. I think Mr. Swaminaithan patented the 1.4 N.A. version too a number of years later. I have seen a patent but I couldn't remember the name, so a search might turn that up. The two have different designs. Both were used in DIC systems. Building a condenser for D.I.C. would mean it would need to be strain free. Something to consider when thinking about doublets.
Last edited by apochronaut on Wed Sep 22, 2021 10:36 pm, edited 1 time in total.

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Re: Aplanatic-Achromatic Condenser Design?

#19 Post by LouiseScot » Wed Sep 22, 2021 10:14 pm

MichaelG. wrote:
Wed Sep 22, 2021 9:17 pm
This one is relatively simple in design, and the optical formula is fully disclosed:
https://worldwide.espacenet.com/patent/ ... US4060306A

But I doubt you will find suitable elements on-the-shelf anywhere. :(

MichaelG.
.
Click on the vertical column of three dots to access the download
Thanks for that. One can buy aspheric lenses but not necessarily exactly as per a given commercial design. I don't think I could easily make one like in the patent. Maybe I'll have to just make do with a simple condenser. Thanks anyway.
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#20 Post by apochronaut » Wed Sep 22, 2021 10:45 pm

Your best bet is an abbe aspheric that were also good for pol. .Simple and straightforward with two or 3 elements. Some of them are 20 or 30 dollars.
Another option is a PZO 1.2 abbe. Those were used in the phase and D.I.C. carousels and given the quality of the PZO D.I.C. must work well enough. They are also cheap. They are a little wider field so the central portion is a little more aberration free.

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#21 Post by LouiseScot » Wed Sep 22, 2021 11:35 pm

apochronaut wrote:
Wed Sep 22, 2021 9:20 pm
Back lens in the case of a condenser is the exit lens . It's usually a rather severe plano/convex lens of variable diameter, sometimes a doublet. The more severe the curvature of the leading surface, the higher the N.A. and of course any of them with an N.A. over 1.0 must be immersed to achieve that.
I built two condensers about 4 or 5 years ago using a factory condenser housing that was carrying an oil immersion back lens and had been ground to achieve a 1.4 N.A. spec.as marked on the upper shroud. The missing lenses would have completed a 1.4 N.A. oil immersion achromat/aplanat. Those blanks are still available. The surplus dealer that has them must have acquired quite a few of them. It's a pretty good blank to work with because the diaphragm housing that carries it, is one of the cheapest commonly available dovetail condenser/diaphragm frames available.
Originally, I was trying to make an oil achromat and an oil apochromat, using a triplet as a front lens. Neither ended up as great oil immersion condensers but one is a very good dry achromat, probably .95 or better. It produces a very bright even illumination. Superior to the factory made .90 achromat/aplanat.
The one with the apochromat front lens turned out to neither be a great dry condenser nor oil condenser. It is well corrected though and seems best suited to water immersion. I haven't evaluated it with glycerin. At this point intuitively, I tend to use the d.i.y. dry condenser usually and next the factory made 1.25 N.A. W.F. abbe aspheric if I want to oil immerse an objective. If the immersed objective is over 1.30 I use the factory 1.4 N.A. achromat/aplanat, which I acquired about 2 or 3 months after my d.i.y. project.z
Michael G posted that S. Krishnaiyer designed condenser patent, while I was tapping away. That is the 1.3 N.A. version of the 1.4 N.A. condenser that I mention above. I think Mr. Krishnaiyer patented the 1.4 N.A. version too a number of years later. I have seen a patent but I couldn't remember the name, so a search might turn that up. The two have different designs. Both were used in DIC systems. Building a condenser for D.I.C. would mean it would need to be strain free. Something to consider when thinking about doublets.
Ah ok. At the moment I have the exit lens from a simple (=cheap!) condenser (actually taken from my Swift 380T) but I had it in mind to maybe try and make something that was hopefully better overall. That's why I was trying to find out the design rationale behind
condenser optics. I think for my purposes it can have an NA<1 and I'll be keeping it dry, so maybe that exit lens need not be so severe. After all, the Swift condenser works surprisingly well considering its simplicity. I bought a second similar one from China for £15 :) Both have the same stock exit lens, I think, and have an apparent NA of 1.25 - whether that's a Chinese 1.25, I'm not sure! I'll have to have a go at measuring their NA as posted by Bram above. Thorlabs sell a selection of Aspheric condenser lenses but only have a max NA of 0.79 though my highest objective is 60x/0.80. Based on that, my condenser need only reach 0.80 also. I guess its the complex shape of some condenser (exit) lenses which furnish them with the very high (>1) NA? But since you can only achieve an absolute max of 1 (less in practice) without oil, maybe it's not such an issue.
If I can't easily improve on the simple condenser I have then I suppose I'll have to make do. I wonder what criteria you used in order to decide if a particular combination of lenses was good/great/not so good? I wonder if I would even be able to spot the difference. My eyesight is not so good these days...
At the moment I've unscrewed the front of the 'Swift' condenser so that I can accommodate the diy polycarbonate dic condenser 'prism' close to it. I may possibly buy a proper Nomarski condenser prism, and maybe also a Nomarski objective prism slider, if I can't get the polycarbonate ones to work. Having actual Nomarskis would actually make the whole design a lot simpler (and probably would work a lot better!) but would defeat the object of what I set out to do!

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#22 Post by MichaelG. » Thu Sep 23, 2021 8:06 am

Have you considered the possibility of adapting a camera, or enlarger, lens to serve as a condenser ?

MichaelG.
Too many 'projects'

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#23 Post by LouiseScot » Thu Sep 23, 2021 9:47 am

MichaelG. wrote:
Thu Sep 23, 2021 8:06 am
Have you considered the possibility of adapting a camera, or enlarger, lens to serve as a condenser ?

MichaelG.
I hadn't, no. I'm not sure why either would be better than the actual condenser lens I currently have? Whatever I use has to fit into my diy dic optical train and needs to have a focal length and working distance commensurate with using the 60x objective and dic prism. In other words it has to emulate a universal/dic condenser and ideally have an NA of at least 0.80. Obviously an actual DIC condenser would be best but they are expensive (even second hand)!

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

LouiseScot
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Re: Aplanatic-Achromatic Condenser Design?

#24 Post by LouiseScot » Thu Sep 23, 2021 11:00 am

BramHuntingNematodes wrote:
Wed Sep 22, 2021 4:28 pm
you should be able to measure it directly by shining a bright light through and have it project on to a card on end
I just had a quick go at measuring the NA of my recently purchased cheap, Chinese condenser by measuring the diameter and distance of the light cone and just using an LED torch (No Kohler!). Firstly, it was impossible to measure with the aperture completely open - the border of the light circle was just too undefined. Unsurprising, really. So I had to stop it down just enough so as to be able to get an image of the aperture blades. At a fixed distance the diameter was about 77mm. The vertical distance from the condenser lens was about 23mm. Anyway, some Pythagoras and Trig gave me a Sine of about 0.86 (all measurements were approximate but to within a few mm). So the condenser may indeed have a potential NA of 1.25 (with oil) but in air it obviously has to be used with the aperture at least slightly closed and will always be <1. An interesting little exercise! If only I had a quality condenser to compare with. Oh well. Still, theoretically, from an NA point of view, I think it should just about be ok to use with my 60x/0.80 air objective. Hopefully. Anyway, I have a better comprehension of, and feel for, NA now :)

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#25 Post by MichaelG. » Thu Sep 23, 2021 11:11 am

LouiseScot wrote:
Thu Sep 23, 2021 9:47 am
MichaelG. wrote:
Thu Sep 23, 2021 8:06 am
Have you considered the possibility of adapting a camera, or enlarger, lens to serve as a condenser ?
I hadn't, no. I'm not sure why either would be better than the actual condenser lens I currently have?

Louise
Mainly because they are aplanatic and achromatic

MichaelG.
Too many 'projects'

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Re: Aplanatic-Achromatic Condenser Design?

#26 Post by LouiseScot » Thu Sep 23, 2021 11:46 am

MichaelG. wrote:
Thu Sep 23, 2021 11:11 am
LouiseScot wrote:
Thu Sep 23, 2021 9:47 am
MichaelG. wrote:
Thu Sep 23, 2021 8:06 am
Have you considered the possibility of adapting a camera, or enlarger, lens to serve as a condenser ?
I hadn't, no. I'm not sure why either would be better than the actual condenser lens I currently have?

Louise
Mainly because they are aplanatic and achromatic

MichaelG.
Maybe but, as mentioned, any lens setup has to physically fit in place and have sufficient NA. Perhaps an aspheric lens combined with an achromatic doublet would do. Or even the condenser exit lens I have, combined with an achromat. I also want to incorporate a Kohler setup. Well, I already have but I think it could be better :)

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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Re: Aplanatic-Achromatic Condenser Design?

#27 Post by apochronaut » Thu Sep 23, 2021 12:10 pm

Do you know if your condenser is strain free?

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Re: Aplanatic-Achromatic Condenser Design?

#28 Post by LouiseScot » Thu Sep 23, 2021 2:22 pm

apochronaut wrote:
Thu Sep 23, 2021 12:10 pm
Do you know if your condenser is strain free?
Hi

It doesn't seem to give any problems with polarized light. Neither does the objective I'm using though I have another objective that is specified for DIC, if it comes to it.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

apochronaut
Posts: 6272
Joined: Fri May 15, 2015 12:15 am

Re: Aplanatic-Achromatic Condenser Design?

#29 Post by apochronaut » Thu Sep 23, 2021 3:15 pm

It is an important point to consider. I suspect that the DIC designation on an objective might in some cases at least, just note that the back focal plane is coherent with the correct prism in the system.
In the case of PZO both planachro and planachro DIC objectives were used, with the DIC objectives substituting for the DIC head, due to their integrated prism. Yes. Integrated prism. A real bargain. The standard planachros required a DIC head with an integrated polarizer ; the DIC objectives required just the polarizer. Might solve a problem for you but might be best with the native condenser.
https://www.ebay.com/itm/255058430881?h ... SwN1Fg9GjU
https://www.ebay.com/itm/324286528165?h ... SwELhfVTtK The price on this one is a little higher than I have seen otherwise. Usually 70.00 or less can be found. PZO did not make a 60X to my knowledge and certainly not with an integrated prism. Just 10X .24 , 20X .40, 40X .65 and 100X 1.25 as DIC planachros.

Just an F.Y.I. I looked into the 1.2 PZO condensers. They are running around 40.00 but when attached to an either slit or carousel prism D.I.C. diaphragm, they are priced higher to reflect their association with DIC.
I have an extra one that arrived on an interference contrast slit diaphragm, so is almost guaranteed to be strain free; unless by some quirk it was a strained cement interloper. I would sell it, since I do not need it.

LouiseScot
Posts: 1167
Joined: Tue Jul 07, 2020 1:51 pm
Location: Scotland

Re: Aplanatic-Achromatic Condenser Design?

#30 Post by LouiseScot » Thu Sep 23, 2021 3:58 pm

apochronaut wrote:
Thu Sep 23, 2021 3:15 pm
It is an important point to consider. I suspect that the DIC designation on an objective might in some cases at least, just note that the back focal plane is coherent with the correct prism in the system.
In the case of PZO both planachro and planachro DIC objectives were used, with the DIC objectives substituting for the DIC head, due to their integrated prism. Yes. Integrated prism. A real bargain. The standard planachros required a DIC head with an integrated polarizer ; the DIC objectives required just the polarizer. Might solve a problem for you but might be best with the native condenser.
https://www.ebay.com/itm/255058430881?h ... SwN1Fg9GjU
https://www.ebay.com/itm/324286528165?h ... SwELhfVTtK The price on this one is a little higher than I have seen otherwise. Usually 70.00 or less can be found. PZO did not make a 60X to my knowledge and certainly not with an integrated prism. Just 10X .24 , 20X .40, 40X .65 and 100X 1.25 as DIC planachros.

Just an F.Y.I. I looked into the 1.2 PZO condensers. They are running around 40.00 but when attached to an either slit or carousel prism D.I.C. diaphragm, they are priced higher to reflect their association with DIC.
I have an extra one that arrived on an interference contrast slit diaphragm, so is almost guaranteed to be strain free; unless by some quirk it was a strained cement interloper. I would sell it, since I do not need it.
Hi

Thanks but, um, remember I'm building this diy dic infinity microscope from scratch, using only basic low-cost components and just on a horizontal rail at the moment, and using the stressed polycarbonate ('Sanderson') dic prisms with a '4f' lens system (to shift what would be the normal position of a Nomarski type dic prism). I only started this extra thread because I was thinking I might need to improve on the simple, cheap condenser I have. But, on reflection, I think it will probably be ok for now. I don't really have a goal of achieving any kind of high quality dic - I'm just tinkering, really :) Mind you, those PZO objectives do seem very cheap! They don't appear on my UK Ebay even though it says will ship internationally.

Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo

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