dIY DIC

Here you can discuss different microscopic techniques and illumination methods, such as Brightfield, Darkfield, Phase Contrast, DIC, Oblique illumination, etc.
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Hugh
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Re: dIY DIC

#31 Post by Hugh » Fri Dec 20, 2019 12:17 am

Hi - just invested in a Nikon Eclipse 55i - which was supposed to be DIC (the objectives have DIC marked on them - but appear to be completely normal objectives (am I missing something?) - there is a polarizer and an analyser (in the headstage) - nothing resembling prisms.
What is missing - there appears to be a dearth of information on this. Also - looking for a x100 (infinity optics) objective for this. Maybe contact me
hugh@austrop.org.au

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wporter
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Re: dIY DIC

#32 Post by wporter » Fri Dec 20, 2019 12:39 am

The objectives marked 'DIC' don't have internal prisms, but rather have high-quality strain-free & occlusion-free optical glass. There is still a need for a prism external to and above the objective, and one below the objective.

See the below page for a nice color graphic (Fig. 1) of a DIC optical system showing the components.

Quote:
"Objectives designed for differential interference contrast must be free of strain or birefringent occlusions that depolarize light and lead to image degradation. In the past, microscopists were limited to strain-free achromat and fluorite objectives intended for observations in polarized light, but modern objectives having higher correction factors can now be employed for DIC microscopy. Termed universal objectives, these advanced lens systems can often be used for combined DIC, fluorescence, phase contrast, and brightfield microscopy without having to change objectives. In addition, newer apochromatic objectives have been designed that are sufficiently strain free to enable their use in polarized light and differential interference contrast observation, dramatically improving the image quality and resolution at higher magnifications."

from https://www.olympus-lifescience.com/en/ ... iguration/

Hugh
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Re: dIY DIC

#33 Post by Hugh » Fri Dec 20, 2019 2:00 am

Thanks for that
Unfortunately my server won't display the link - seems it has security issues.. (?!)

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RobBerdan
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Re: dIY DIC

#34 Post by RobBerdan » Mon Jan 20, 2020 5:39 am

I have DIC, Hoffman and I used oblique illumination which the article refers to. I believe the author has now purchased DIC. DIC is unfortanetly very expensive to make. A number of researchers have been working on developing software that is supposed to simulate DIC or Phase contrast, but none has answered my emails. Still I believe it will come in the future.

Oblique illumination can easily be created by simply moving your filter holder to partially obscure the incoming light. It might work better with certain objectives. Hoffman modulation - simulates DIC but only in Black and white and is useful because most forms of DIC can't be used with plastic tissue culture dishes. Zeiss offers a version of DIC for plastic dishes, but it is inferior to real DIC.

Below I have attached 3 images 1) Hoffman Modulation contrast 2) Oblique pseudo DIC and 3) Real DIC
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rmb
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Re: dIY DIC

#35 Post by rmb » Sat Apr 18, 2020 12:39 pm

I have a method called varable amplitude contrast (VAC) working and it compares very, very favourably with DIC although it works in a different way. It involves 3 pieces of polarised film. 2 are arranged to make a stops for each objective (this is the hardest part to make) which are fitted into a phase condenser so they are in the right focal plane. The other rotates over the light well. No special objectives are needed. It also gives superior dark field
The method was described in an issue of the balsam post a few years back.
I dont know why it isnt used by more people

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75RR
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Re: dIY DIC

#36 Post by 75RR » Sat Apr 18, 2020 12:54 pm

The method was described in an issue of the balsam post a few years back.
I dont know why it isnt used by more people
Can you provide a link to it?
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Roldorf
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Re: dIY DIC

#37 Post by Roldorf » Sat Apr 18, 2020 2:51 pm

For Those looking for a link to the Balsam Post and the above Variable contrast method VAC see here for some images:-
https://postalmicroscopicalsociety.gith ... trast.html

For an explanation of the method see this post from the old Microbehunter forum:-

http://www.microbehunter.com/forum/spec ... hod-vac-2/


It seems only one of the suppliers of the polarizing film still have it available:

http://www.greenweld.co.uk/acatalog/Pol ... _Film.html
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75RR
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Re: dIY DIC

#38 Post by 75RR » Sat Apr 18, 2020 3:28 pm

Thanks Roldorf - good sleuthing!
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Roldorf
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Re: dIY DIC

#39 Post by Roldorf » Sun Apr 19, 2020 8:57 am

Nahh, good search engine:- www.startpage.com billed as (The world's most private search engine) instead of using google. I use this as my preferred search engine.
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nelson
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Re: dIY DIC

#40 Post by nelson » Wed Apr 21, 2021 5:26 pm

Hello Everyone,

I've been lurking in the shadows here for some time - first visit many years ago and now back again.

I know this is a fairly old thread, but I daringly open it up again as I just noted some quite new information on the subject and would like to share it.

There's an article published last year titled "Differential interference contrast microscopy with adjustable plastic Sanderson prisms" that may reveal a plausible path for DYI DIC. It's available here (for a fee): https://www.osapublishing.org/ao/abstra ... 59-11-3404

The actual prism and its initial construction is described here (free for the taking): https://authors.library.caltech.edu/6948/1/SANrsi05.pdf

The PDF is quite mathematically oriented, but also shows actual results as well as very good images of the prism and its construction.

Hope this sparks som new ideas - enjoy! :)


Cheers,

Nelson

Saul
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Re: dIY DIC

#41 Post by Saul » Wed Apr 21, 2021 6:26 pm

nelson wrote:
Wed Apr 21, 2021 5:26 pm
...There's an article published last year titled "Differential interference contrast microscopy with adjustable plastic Sanderson prisms" that may reveal a plausible path for DYI DIC. It's available here (for a fee): https://www.osapublishing.org/ao/abstra ... 59-11-3404

The actual prism and its initial construction is described here (free for the taking): https://authors.library.caltech.edu/6948/1/SANrsi05.pdf

The PDF is quite mathematically oriented, but also shows actual results as well as very good images of the prism and its construction...
https://www.photomacrography.net/forum/ ... 70#p269570
https://www.microbehunter.com/microscop ... =Sanderson

nelson
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Re: dIY DIC

#42 Post by nelson » Wed Apr 21, 2021 7:19 pm

Saul wrote:
Wed Apr 21, 2021 6:26 pm
nelson wrote:
Wed Apr 21, 2021 5:26 pm
...There's an article published last year titled "Differential interference contrast microscopy with adjustable plastic Sanderson prisms" that may reveal a plausible path for DYI DIC. It's available here (for a fee): https://www.osapublishing.org/ao/abstra ... 59-11-3404

The actual prism and its initial construction is described here (free for the taking): https://authors.library.caltech.edu/6948/1/SANrsi05.pdf

The PDF is quite mathematically oriented, but also shows actual results as well as very good images of the prism and its construction...
https://www.photomacrography.net/forum/ ... 70#p269570
https://www.microbehunter.com/microscop ... =Sanderson
Now... That's plain beautiful! Thanks!

I did look around, but obviously I didn't do it well enough.

I will carefully have a look att your work with this before I start asking all the questions lining up.

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Re: dIY DIC

#43 Post by jmp » Wed Apr 21, 2021 9:49 pm

...There's an article published last year titled "Differential interference contrast microscopy with adjustable plastic Sanderson prisms" that may reveal a plausible path for DYI DIC. It's available here (for a fee): https://www.osapublishing.org/ao/abstra ... 59-11-3404
That paper was mentioned in the 2021 meeting reports from the Quekett Microscopical Club and the pdf is visible here, in case someone can't get through the article paywall.

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Re: dIY DIC

#44 Post by nelson » Wed Apr 21, 2021 10:20 pm

Thank you very much!

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Re: dIY DIC

#45 Post by BramHuntingNematodes » Thu Apr 22, 2021 2:09 am

Holy smokes do you see how that works? You bend the prism!
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

LouiseScot
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Re: dIY DIC

#46 Post by LouiseScot » Fri Apr 23, 2021 1:11 pm

Hi all

The 'Sanderson Prism' idea looks interesting and relatively easy to implement. In the paper their lens 2 is 80mm diameter! Not sure why that should be other than it just happened to be a lens they had easy access to. Else maybe it was to go with the larger 'open frame' prism holder? Surely a duplicate of the condenser prism holder would do? Lens 1 is a more standard 25.4mm (1").
I think I might have a go at putting together one of these DIC-type setups :) . They don't give exact details of the working of the condenser prism holder but I guess it just follows the same principles as the frame prism holder so shouldn't be too difficult to hack. I assume they just put the frame holder together based on Sanderson's paper/design and adapted it for the DIC.
Anyone else fancy having a go?

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: dIY DIC

#47 Post by jmp » Fri Apr 23, 2021 6:02 pm

Anyone else fancy having a go?
Yes. I have an inverted microscope that provides easy slider access to the condenser and to the back focal plane of the objective. I have the original phase sliders and also a condenser silt slider (and polarizer). The slit slider is used in conjunction with a wolaston prism slider for 10x and 20x 'PlasDIC' (but I don't have it). This setup was useful to tests 3D printed sliders that I built to play with 'variable asymmetric contrast' (VAC2), which give a really nice oblique and darkfield contrast for low power. It should be relatively easy to design and 3D print sliders to hold Sanderson Prisms (basically a polycarbonate bar if I'm reading this correctly) and screws to adjust the lateral stress on them. I already ordered a small piece of polycarbonate from ebay ($10 or so), similar to the one described in one of the papers mentioned above. Would be fun to play with this... another little project to add to an already long list...

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Re: dIY DIC

#48 Post by LouiseScot » Fri Apr 23, 2021 7:17 pm

jmp wrote:
Fri Apr 23, 2021 6:02 pm
Anyone else fancy having a go?
Yes. I have an inverted microscope that provides easy slider access to the condenser and to the back focal plane of the objective. I have the original phase sliders and also a condenser silt slider (and polarizer). The slit slider is used in conjunction with a wolaston prism slider for 10x and 20x 'PlasDIC' (but I don't have it). This setup was useful to tests 3D printed sliders that I built to play with 'variable asymmetric contrast' (VAC2), which give a really nice oblique and darkfield contrast for low power. It should be relatively easy to design and 3D print sliders to hold Sanderson Prisms (basically a polycarbonate bar if I'm reading this correctly) and screws to adjust the lateral stress on them. I already ordered a small piece of polycarbonate from ebay ($10 or so), similar to the one described in one of the papers mentioned above. Would be fun to play with this... another little project to add to an already long list...
Oh good! Maybe we can compare notes. I've ordered some 3mm polycarbonate sheet off Ebay (can't get 3/32" here!). I'll have a go at designing a holder similar to the condenser one in the paper. It's a pity the authors didn't show the inner workings of their one but I figure it must be similar, in principle, to the larger open frame.

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

Greg Howald
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Re: dIY DIC

#49 Post by Greg Howald » Sat Apr 24, 2021 10:08 am

All I did was download the image of the filter being used, adjust the size for my scope and cut it out of black card stock. Upon first use I was immediately impressed. I did a little tweaking with it and it works really well. I didn't look at any science behind it. I just applied the knowledge. Thanks for this. It is appreciated.
Greg

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essence25
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Re: dIY DIC

#50 Post by essence25 » Sat Oct 15, 2022 11:00 pm

I found these LOMO? inverted microscope DIC prisms, the upoer bigger one has a circular glass and a secondary slit with another glass behind it. The lower has a clear squarish prism glued at the edges.
Can I do a anything with these to obtain some form of DIC?



Last edited by essence25 on Mon Oct 17, 2022 5:04 pm, edited 3 times in total.

LouiseScot
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Re: dIY DIC

#51 Post by LouiseScot » Sat Oct 15, 2022 11:12 pm

Hi

Have a look at this thread: viewtopic.php?t=8704#p75548

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

Scarodactyl
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Re: dIY DIC

#52 Post by Scarodactyl » Sun Oct 16, 2022 4:15 am

Nice find!

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Re: dIY DIC

#53 Post by jmp » Mon Oct 17, 2022 2:51 am

essence25 wrote:
Sat Oct 15, 2022 11:00 pm
I found these LOMO? or whatever DIC prisms, the upoer bigger one has a circular glass and a secondary slit with another glass behind it. The lower has a clear squarish prism glued at the edges.
Can I do a anything with these to obtain some form of DIC?

The link that you shared appears to be broken. Can you share another one or an image of these? I believe these are the sliders for a LOMO inverted microscope. If I'm correct, the big upper slider is just a polarizer and a slith, the smaller lower slider is a Wollaston prism. Both are used with 10 and 20x LOMO objectives for DIC. There's also upper and lower sliders for phase.

I have the big slider and I have been looking for ages for the smaller slider, and I'm interested in buying it, in case it's for sale.
In the meantime I've been experimenting with a Sanderson prism as a replacement, and lately I got really close to having DIC working. I'll share some images soon.

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essence25
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Re: dIY DIC

#54 Post by essence25 » Mon Oct 17, 2022 4:48 pm

Thank you for letting me know. Updated! Send me a PM...

jmp
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Re: dIY DIC

#55 Post by jmp » Mon Oct 17, 2022 7:38 pm

essence25 wrote:
Mon Oct 17, 2022 4:48 pm
Thank you for letting me know. Updated! Send me a PM...
PM sent.

Sure Squintsalot
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Re: dIY DIC

#56 Post by Sure Squintsalot » Tue Nov 08, 2022 5:27 am

So, I gave this "adjustable plastic Sanderson prism" build a try. What motivated me was the idea that, for less than $10, I could couple the plastic Sanderson prism on the condenser side to my existing quartz Normarski prisms on the objective side. Before getting too involved in a time-consuming, quality build, I first had to slap something together that would at least pass "the smell test":

To start with, I had two index card sized sheets of polarizing film and an old fluorescent light table, crossing the pols on the sheets and slipping an old plastic circle template between reveals the characteristic birefringence colors of stressed plastic. At least I had a few basic tools to verify some functions:
Screenshot 2022-11-07 214628.jpg
Screenshot 2022-11-07 214628.jpg (113.8 KiB) Viewed 7091 times
In my rudimentary workshop, I cut a far too thick piece of plexiglass to indicated length and width, fashioned the vise blocks out of some old walnut I had laying around, then squeezed the crap out of it with a woodworkers clamp while looking at it through my polarizer set-up:
Screenshot 2022-11-07 215954.jpg
Screenshot 2022-11-07 215954.jpg (67.75 KiB) Viewed 7091 times
I was actually impressed by how linear the deformation was; I was expecting more of an arc. The next step was fooling around with the polarizers and compression:
Screenshot 2022-11-07 220722.jpg
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Screenshot 2022-11-07 220947.jpg
Screenshot 2022-11-07 220947.jpg (72.53 KiB) Viewed 7091 times
The harder I squoze the clamp, the tighter the birefringent banding. There was also a clear difference to the color order between the compressed side and the tensioned side. After a couple of hours of this head-scratching amusement, I placed the unit over the field lens and was immediately disappointed. It didn't fit.
After lopping off the corners, it finally fit, but just barely, and I managed to get about 90 degrees of rotation. It was cool to see the banding on the nomarski prisms when viewed through the eyetube. Not having a third arm, I couldn't get any photos.

Did it work? Sorta, not really. But I see a clear path to excellent results. More later.

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Re: dIY DIC

#57 Post by Scarodactyl » Tue Nov 08, 2022 5:35 am

Cool! Looks great so far. Will wait for updates with bated breath.

LouiseScot
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Re: dIY DIC

#58 Post by LouiseScot » Tue Nov 08, 2022 5:30 pm

Hi

I have to admit, I haven't revisited this (despite intending to!). My small prism holders seemed to work - the amount of pressure/tension needed by the screws to produce the right banding and spacing was much smaller than I had anticipated originally. I think the problem I ran into was not knowing how to scale things for the condenser side in order to get the hoped-for deflections right. In the end, I decided that it would be too difficult without some sort of measuring device (as used in the paper) or a proper prism to compare with (also as used in the paper). Obviously, if I had a proper prism then there would be no need to mess about with the polycarbonate ones! I could certainly get the 'raw bands' to favourably compare to what you expect to see. I probably am not going to waste any more time on it. I bought a Nikon Optiphot DIC nosepiece which was in very good condition and which I got quite cheaply on Ebay. It's really just for reflective DIC and has prisms for 5x, 20x, and 2 x (10/40/100x). I've been beavering away (on and off) making an epi/vertical illuminator for my diy rail scope. It may need some adjustment and/or a way to properly centre the field iris but the basic thing is working and incorporates a polarizer. I get a nice sharp image of the field iris at the specimen plane. I've so little time at the moment but, hopefully, I'll be able to actually try some reflective DIC in December (it's what Christmas is for!). I only have a 5x DIC epi objective but that's a start, if it all works. If ok, I might try and get it to work in transmission mode but I'm not sure what prism I could use/afford to buy for the condenser side so that step might never happen!

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

Sure Squintsalot
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Re: dIY DIC

#59 Post by Sure Squintsalot » Tue Nov 08, 2022 6:40 pm

I totally understand the frustrations of the DIY'er, especially for such finely complicated stuff as manipulating wavelengths of light. Epi DIC can be nothing short of spectacular and 5x is not a bad start, though 20x is probably the sweet spot. I've read that DIC-specific objectives are not critical, so long as the glass within is strain-free.

Some wicked cool materials to look at: Home-grown alum crystal face from a Smithsonion crystal growing kit:
Screenshot 2022-11-08 112830.jpg
Screenshot 2022-11-08 112830.jpg (180.32 KiB) Viewed 7034 times
Cleavage plane of a freshly split calcite crystal:
Screenshot 2022-11-08 113232.jpg
Screenshot 2022-11-08 113232.jpg (196.71 KiB) Viewed 7034 times
Terminal crystal face of a plain old quartz crystal:
Screenshot 2022-11-08 113408.jpg
Screenshot 2022-11-08 113408.jpg (147.13 KiB) Viewed 7034 times
Machining marks of finely milled Leitz aluminum part:
Screenshot 2022-11-08 113536.jpg
Screenshot 2022-11-08 113536.jpg (246.22 KiB) Viewed 7034 times
Surface of a petrographic thin section with metal inclusions:
Screenshot 2022-11-08 113911.jpg
Screenshot 2022-11-08 113911.jpg (211.37 KiB) Viewed 7034 times

LouiseScot
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Re: dIY DIC

#60 Post by LouiseScot » Tue Nov 08, 2022 7:30 pm

Nice images! I only have the 5x which is an Epi dic objective, but I have a 20x Nikon dic apo and a 40x Nikon dic fluor, but neither is specified for Epi - but might be worth a try.

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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