Question about lighting method for leaf, pollen, hair, gem?

[fsittony]

Hi all,
What will be the best lighting method for leaf, pollen, hair, gem on a microscope? Trasmitted light is not workable as the specimen is not transparent.
EPI illumination is good for metal, but I don't find it's pleasing for leaf, pollen and gem.
EPI DIC might not be useful for these kinds of specimen.
How about EPI with darkfield, will it be any help? I'm also looking for the suitable objectives, if darkfield is not useful, I'll pass all the BD objectives then.
Is it better if lighting is from the side? In this way, fiber lighting seems to be the best choice, then what will be the minimum Working Distance for such specimen?
I checked the specification of Olympus metallurgical objectives, high manification objectives say Mplanfl 50x, 100x only have WD less than 1mm, which is not possible for side lighting...
How about Lmplanfl, Na looks much lower than Mplanfl, but the WD is good, about 10mm.
Thanks.
Tony

[Scarodactyl]

For gems oblique illumination is kind of king, particularly with fiber optic light guides. High NAs get restrictive for inclusions because you're shooting through a high RI medium so 50x and 100x objectives are more niche for gem work. The ideal objectives are mitutoyo m plan apos because of their longer working distance and superior color correction, but they are kind of expensive.

[MicroBob]

Hi Tony,

leaf: Epi brightfied, epi darkfield, epi pol Or: flat section, transmitted brightfield, example attatched.
pollen: Transmitted brightfield
hair: Transmitted or epi brightfield. In air you will see the surface, here epi is better. In a medium of similar refractive index you will look into the hair, here transmitte is better.

Generally I find it difficult to get good contrast in epi brightfield, pol is much better and easy to improvise.

Bob

[fsittony]

For gems oblique illumination is kind of king, particularly with fiber optic light guides. High NAs get restrictive for inclusions because you're shooting through a high RI medium so 50x and 100x objectives are more niche for gem work. The ideal objectives are mitutoyo m plan apos because of their longer working distance and superior color correction, but they are kind of expensive.

Got it. Mitutoyo are definitely the king. With my stand BH2, it won't have enought working distance. I might use LMPLANFL at the moment, at least it looks brighter and have more contrast than the NEO SPLAN.
I wonder how much difference it would have comparing to Mitu.
Tony

[fsittony]

Hi Tony,

leaf: Epi brightfied, epi darkfield, epi pol Or: flat section, transmitted brightfield, example attatched.
pollen: Transmitted brightfield
hair: Transmitted or epi brightfield. In air you will see the surface, here epi is better. In a medium of similar refractive index you will look into the hair, here transmitte is better.

Generally I find it difficult to get good contrast in epi brightfield, pol is much better and easy to improvise.

Bob

Hi Bob,
That's great information. I will keep it as reference.
I agree, EPI brightfield doesn't have good contrast, POL and Darkfield are much better. Maybe I will also use fiber optics from the side.
I tried EPI DIC, but it's not satisfying as the doubling seems to be a big problem, same as Scarodactyl's BH2.
viewtopic.php?p=113766#p113696
Subject is a RAM and it is quite flat. Not to tell the image quality of leaf and pollen stuff.
I don't know if there is any compatiablitiy problem with the DIC prism ULWD and polarizer UPO. The original prism should be M-NIC/N-NIC.
From trasmitted DIC, I loves working on it and it doesn't have any doubling problem.
Tony

[Adam Long]

Tony,

I don't know how epi-darkfield works on the Olympus, but on my Zeiss Universal it's my usual choice for opaque subjects. For most natural subjects like plants and rocks it is more like Lieberkühn - just a nice, very diffuse top light - but you get a true darkfield effect on subjects like coins where it picks out the relief on a flat reflective metal surface very effectively. Also, unlike some other epi lighting methods, there are no mirrors or beam splitters in the light path to degrade image quality and cause reflections. For stacking there is an additional benefit that illumination falls off very quickly above the focal plane, so out-of-focus highlights only occur below focus.

[EYE C U]

Screen Shot 2021-11-17 at 10.11.58 AM.png (331.11 KiB) Viewed 5429 times

[Scarodactyl]

I dig it. Curious about the poseable arm bit--any chance you have a link to that product?

For gems oblique illumination is kind of king, particularly with fiber optic light guides. High NAs get restrictive for inclusions because you're shooting through a high RI medium so 50x and 100x objectives are more niche for gem work. The ideal objectives are mitutoyo m plan apos because of their longer working distance and superior color correction, but they are kind of expensive.

Got it. Mitutoyo are definitely the king. With my stand BH2, it won't have enought working distance. I might use LMPLANFL at the moment, at least it looks brighter and have more contrast than the NEO SPLAN.
I wonder how much difference it would have comparing to Mitu.
Tony

You will probably find gems hard to work with on a biological stand even with short objectives. They're thick and require three dimensional manipulation, and typical stages just don't go low enough. An inverted stand might be easier to adapt, or preferrably a stand where the head moves across a much wider range of positions.
In terms of image quality the olympus fluors are not bad at all but do have a smaller image circle and more CA.

[fsittony]

Tony,

I don't know how epi-darkfield works on the Olympus, but on my Zeiss Universal it's my usual choice for opaque subjects. For most natural subjects like plants and rocks it is more like Lieberkühn - just a nice, very diffuse top light - but you get a true darkfield effect on subjects like coins where it picks out the relief on a flat reflective metal surface very effectively. Also, unlike some other epi lighting methods, there are no mirrors or beam splitters in the light path to degrade image quality and cause reflections. For stacking there is an additional benefit that illumination falls off very quickly above the focal plane, so out-of-focus highlights only occur below focus.

Hi Adam Long,
I attached some pictures of a coin with Darkfield, Brightfield, POL, and DIC. Objective is LMPLANFL 10X. Do they look similar from your Zeiss?





Darkfield got better contrast than Brightfield. But I don't got enough brightness from my eyeview. This is still 10x, not to mention the high maginification, although it's ok to slow down the shutter speed for shooting.
I doubt the low brightness would affect the detail?

How do you like EPI DIC? Can you post some pictures?
From my stand, it's not satisfying, it looks like doubling. The edges are not clear as Darkfield, Brightfield, POL. With such results, stacking would be a big problem.
Tony

[fsittony]

I dig it. Curious about the poseable arm bit--any chance you have a link to that product?

For gems oblique illumination is kind of king, particularly with fiber optic light guides. High NAs get restrictive for inclusions because you're shooting through a high RI medium so 50x and 100x objectives are more niche for gem work. The ideal objectives are mitutoyo m plan apos because of their longer working distance and superior color correction, but they are kind of expensive.

Got it. Mitutoyo are definitely the king. With my stand BH2, it won't have enought working distance. I might use LMPLANFL at the moment, at least it looks brighter and have more contrast than the NEO SPLAN.
I wonder how much difference it would have comparing to Mitu.
Tony

You will probably find gems hard to work with on a biological stand even with short objectives. They're thick and require three dimensional manipulation, and typical stages just don't go low enough. An inverted stand might be easier to adapt, or preferrably a stand where the head moves across a much wider range of positions.
In terms of image quality the olympus fluors are not bad at all but do have a smaller image circle and more CA.

Do you mean by this one like stereo type?
http://www.alanwood.net/downloads/olymp ... ochure.pdf

1.jpg (15.7 KiB) Viewed 5397 times

Right, from BH2, I could only extend the substage up and down by 2cm, working distance is quite limited.
I'm not satisfied with the DIC effect. Might work a while with other viewing modes at the moment.
Lmplanfl seems to work ok on BH2,better contrast and high brightness than old NEOSPLANs. It has some problem in DIC, but ULWD NEOSPLAN performs almost the same.
Tony

[eKretz2]

Tony,

I don't know how epi-darkfield works on the Olympus, but on my Zeiss Universal it's my usual choice for opaque subjects. For most natural subjects like plants and rocks it is more like Lieberkühn - just a nice, very diffuse top light - but you get a true darkfield effect on subjects like coins where it picks out the relief on a flat reflective metal surface very effectively. Also, unlike some other epi lighting methods, there are no mirrors or beam splitters in the light path to degrade image quality and cause reflections. For stacking there is an additional benefit that illumination falls off very quickly above the focal plane, so out-of-focus highlights only occur below focus.

Hi Adam Long,
I attached some pictures of a coin with Darkfield, Brightfield, POL, and DIC. Objective is LMPLANFL 10X. Do they look similar from your Zeiss?





Darkfield got better contrast than Brightfield. But I don't got enough brightness from my eyeview. This is still 10x, not to mention the high maginification, although it's ok to slow down the shutter speed for shooting.
I doubt the low brightness would affect the detail?

How do you like EPI DIC? Can you post some pictures?
From my stand, it's not satisfying, it looks like doubling. The edges are not clear as Darkfield, Brightfield, POL. With such results, stacking would be a big problem.
Tony

I don't know about the rest of you, but I don't see any images here.

[fsittony]

I edited the link again, it should work now
Tony

[fsittony]

Screen Shot 2021-11-17 at 10.11.58 AM.png

How much luminosity does your torch have? It's an easy and friendly lighting system.
I tried mine Nitecore R5, but it seems not having enough brightness, especially for the darkfield, pol, dic and high magnificaion.
The light disperses too much, cannot concentrate to produce enough brightness.
Tony

[Scarodactyl]

Do you mean by this one like stereo type?
http://www.alanwood.net/downloads/olymp ... ochure.pdf
1.jpg

Yes, the bhmj is a good option, great fine focus, though it takes an almost comicly thin post which might allow more vibrarion than you'd like. I haven't tried it myself though. They also made the STM series measuring microscopes which are ultra heavy duty but with the same general design concept. There are third party ones that sometimes come up on eBay from the 80s semiconductor heyday of various constructions.

[fsittony]

Interesting module, a mixture of the compound and typical stereo stand. Doesn't have XY stage, but with fine focus and high magnification objectives.
I wonder if could remove BH2's substage and DIY a lower rotary stage then the working distance would extend to 5cm. STM is definitely great type for all kinds of metallurgical subjects except the huge size.
Tony

[eKretz2]

Could always just go pick up one of these:

https://microscopecentral.com/products/ ... kfield-dic

I mean, if you win the lottery or something, heh.

[EYE C U]

I dig it. Curious about the poseable arm bit--any chance you have a link to that product?

you have to do some drill and tapping but it works.

i have a tiffen series filter holder on my other scope.

Screen Shot 2021-11-18 at 11.13.23 AM.png (368.65 KiB) Viewed 5315 times

Screen Shot 2021-11-18 at 11.09.29 AM.png (132.36 KiB) Viewed 5315 times

[Adam Long]

Hi Adam Long,
I attached some pictures of a coin with Darkfield, Brightfield, POL, and DIC. Objective is LMPLANFL 10X. Do they look similar from your Zeiss?

Yes they do. The Zeiss darkfield is achieved with special surrounds for the objectives, is that the same for Olympus?

Darkfield got better contrast than Brightfield. But I don't got enough brightness from my eyeview. This is still 10x, not to mention the high magnification, although it's ok to slow down the shutter speed for shooting.
I doubt the low brightness would affect the detail?

DF does eat a lot of light, I only have a 30W illuminator so have to make sure it is aligned and that the condenser and field iris are fully open. But it is fine for visual, and for photography long shutter speeds are not such a problem with these subjects.

How do you like EPI DIC? Can you post some pictures?
From my stand, it's not satisfying, it looks like doubling. The edges are not clear as Darkfield, Brightfield, POL. With such results, stacking would be a big problem.
Tony

I don't have Epi DIC yet, but my first objective and prism is on the way. I think for any of these lighting methods they have subjects for which they are better suited, the trick is to find out which.

[fsittony]

BD objectives are bigger than the normal ones, as they have darkfield annulis outside the normal objective and light would go through the shell.
Ye, I have to fully open the field aris and aperture too for DF, although I have a 100W illuminator.
Please let me know if you would have any doubling issue when your DIC arrives.
Tony