Recommendations for 40x-100x Objective, LWD, High n.a.?

Everything relating to microscopy hardware: Objectives, eyepieces, lamps and more.
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heyitsmedusty
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Recommendations for 40x-100x Objective, LWD, High n.a.?

#1 Post by heyitsmedusty » Tue Mar 28, 2023 7:20 pm

I'm looking for objectives that meet the following criteria:

1. Magnification anywhere from 40x - 100x
2. As long of a working distance as possible
3. As high of n.a. as possible
4. Either infinity corrected or finite are fine (I can adjust my setup for either)
5. Good for reflected light
6. No cover slip correction

I photograph micrometeorites, which range in size from 80um to 400um (semi-spherical). They are solid specimen, so I must use reflected light. This means I need as much working distance as possible to get good angles of light onto the subject.

I'm fine with modern/vintage/cheap/expensive/etc, really just whatever would have the best resolving power at long distances, and works well with dry specimen.

Thank you for your recommendations! I attached an image to show an example of my work, as a typical subject.


v-type-small.jpg
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apochronaut
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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#2 Post by apochronaut » Tue Mar 28, 2023 8:21 pm

That's a really interesting and important project. I'm curious though, how you adjust your optical system to accept either finite or infinity corrected objectives? I've thought about this some and it is theoretically possible.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#3 Post by Phill Brown » Tue Mar 28, 2023 9:21 pm

I'd be interested to know what would be a good substitute for a micrometeorite to test out some options.
I have no experience with the subject.
I'd likely go for best lower n/a as image stacking is something I still haven't got to.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#4 Post by shutterbug » Wed Mar 29, 2023 12:43 am

I believe the best microscope lenses for photography with a long working distance are the Mitutoyo M PLAN APO lenses - but they are very expensive.

They have a regular "Plan APO" lineup for long working distance and "Plan APO Super Long" working distance.

Between 40x-100x there are 4 lenses:

The "regular" 50x has a WD of 13mm with a NA of 0.55. (approx. 3.100€)
The SL 50x has a WD of 20.5mm and a NA of 0.42.(approx. 4.100€)

The "regular 100x has a WD of 6mm with a NA of 0.70. (approx. 4.000€)
The SL 100x has a WD of 13.0mm and a NA of 0.55. (approx. 5.700 €)


There's also a "HR" series for even more resolution but those have a rather short working distance and they are even more expensive.

They are all equipped with M26 threads.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#5 Post by PeteM » Wed Mar 29, 2023 1:33 am

As Shutterbug says, the Mitutoyo long working distance M Plan Apos are probably the gold standard, but they are expensive and often damaged when sold used.

Since both the working distance and the depth of field tend to get smaller with higher magnifications, there may be a couple of things you can do to get good images from lesser objectives.

1) You'll need more images for focus stacking, so the rigidity of the focus stacking setup comes into play.

2) You'll have less space to bring in light from the side, so things like small fiber optic illuminators, and making creative use of the darkfield, polarization, and BF available through your epi illuminator (which you're not using at lower magnification?) can come into play. I'd think you could also set it up to do oblique lighting. And the ping-pong ball diffuser (you're already using?) can be effective.

Scarodactyl is likely to come along - he may have better advice for you. There has also been a lot of lens testing done by members over at the photomacrography forum - they have advice on affordable higher power epi objectives.

Olympus made "ULWD" epi objectives. Something like the 50x MPlan ULWD (and even higher magnifications) sometimes shows up at a reasonable cost. By reputation, it's not in the same class as Mitutoyo.

Regular MPlan objectives might work for you if you can use the epi illuminator and focus stacking, with maybe a highlight or so coming from the side. There won't be much working distance, but examples from Mitutoyo, recent Unitron, Akashi and, of course, Nikon and Olympus are comparatively affordable. At one time there was a long working distance version meant for hardness testers, sold cheap on Ebay, with a very wide field, high numerical aperture, and long working distance.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#6 Post by Scarodactyl » Wed Mar 29, 2023 2:11 am

I'm on the hunt for a similar objective. Mitutoyo 50x/0.55s are good but the image is kind of soft because of the low NA. The HR variants are all very expensive unfortunately. There are chinese 50x/0.65 and 0.75 mitutoyo-alikes that are around 1300usd new but chromatic aberrations are probably not very well controlled. You can also aim for an Olympus lmplan or one of the chinese clones. Nikon has elwd 210 and infinity variants of their 40x/50x metallurgical objectives, these will have some axial CA but give a pretty good image. The newer ones tend to be pretty darned expensive.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#7 Post by Adam Long » Wed Mar 29, 2023 12:17 pm

I have a Zeiss LD-Epiplan 40x/0.60 which might worth a look. They are not common on the used market but not sought after; mine was £50.

I will have to check the working distance but from memory it is a few mm.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#8 Post by Jose Antonio Mena » Wed Mar 29, 2023 3:54 pm

Hi

There are dark field epi-iluminators from different brandes. I think that that´s the way for your subjects. Whith that equipment you needn´t long working distance objectives, because the ilumination come from the outer barrel of the same objective. You can work with polarized ligth, and apply a retarder before the analizer for change the apearence of the surface of your micrometeorite.

I have a nikon optiphot I, with Dark Field / bright field epi iluminator; finite 210 BD objectives 2,5X, 5X, 10X, 20X, 40X, 60X (you have plan and plan apo...) and I think that could match fully with your work. Other brands have similar equipments. Of course you will need stack the images.

If you want, and when I´ll have a few time, I can send you a photo of the microscope assembly.

Can you show us how is your workflow with the micro-meteorites?

Best regards

JA

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#9 Post by heyitsmedusty » Wed Mar 29, 2023 6:04 pm

apochronaut wrote:
Tue Mar 28, 2023 8:21 pm
That's a really interesting and important project. I'm curious though, how you adjust your optical system to accept either finite or infinity corrected objectives? I've thought about this some and it is theoretically possible.
Here is my current setup:
Stand: Olympus BH
Head: Olympus BH trinocular
Attachments: BH2-UMA vertical illuminator, trinocular port adapter w/ NFK 2.5x
Objectives: Olympus LMPlanFL 20x/0.40 Bd, Nikon CF Plan 40x/0.65 BD (outer barrel removed), LWD NEOSPlan 50x/0.55

The vertical illuminator allows me to use infinity corrected optics. To use finite objectives I just remove the vertical illuminator from between the head and the stand. I should note, I only use the vertical illumination as a "spotlight" for centering my subject, but never for photography. For photography, I crafted a very small ring light + diffuser that mounts to the objective for even lighting around the subject. In my initial image above, you can see the rings of light reflected back in the glassy sphere, with the glass of the objective lens itself reflected back as the dark circle in the middle.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#10 Post by heyitsmedusty » Wed Mar 29, 2023 6:09 pm

Phill Brown wrote:
Tue Mar 28, 2023 9:21 pm
I'd be interested to know what would be a good substitute for a micrometeorite to test out some options.
I have no experience with the subject.
I'd likely go for best lower n/a as image stacking is something I still haven't got to.
You could use any single grain of sand as a good substitute, as that is essentially what I'm looking through to find them. The average size is about 300um (0.3mm), which is just about the size of a period on your screen > .

For my photos, I put the individual MM on a piece of double sided tape stuck to a slide I painted black. I found this helps with contrast the most, as glass or a white background s scatters a lot of photons back up into the lens.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#11 Post by heyitsmedusty » Wed Mar 29, 2023 6:18 pm

Jose Antonio Mena wrote:
Wed Mar 29, 2023 3:54 pm
Hi

There are dark field epi-iluminators from different brandes. I think that that´s the way for your subjects. Whith that equipment you needn´t long working distance objectives, because the ilumination come from the outer barrel of the same objective. You can work with polarized ligth, and apply a retarder before the analizer for change the apearence of the surface of your micrometeorite.

I have a nikon optiphot I, with Dark Field / bright field epi iluminator; finite 210 BD objectives 2,5X, 5X, 10X, 20X, 40X, 60X (you have plan and plan apo...) and I think that could match fully with your work. Other brands have similar equipments. Of course you will need stack the images.

If you want, and when I´ll have a few time, I can send you a photo of the microscope assembly.

Can you show us how is your workflow with the micro-meteorites?

Best regards

JA
I just posted my setup a couple posts above this, so take a look!

I do use a vertical illuminator, but mostly for inspection and subject spotting. I don't use vertical lighting for the photos though, as the directly-reflected light tends to flatten the image and lose a lot of the texture I'm looking to capture. I like to think of my images as portraits, and the analogous lighting to vertical vs oblique in my subjects would be like taking someone's portrait with a camera-mounted flash directed at their face, vs a soft box set to the sides or a very large ring light.

Image attached of a vertically-illuminated subject.
CC-165x.jpg
CC-165x.jpg (154.71 KiB) Viewed 3489 times

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#12 Post by heyitsmedusty » Wed Mar 29, 2023 6:30 pm

Jose Antonio Mena wrote:
Wed Mar 29, 2023 3:54 pm
Can you show us how is your workflow with the micro-meteorites?
Workflow for micrometeorite image capture:
  1. Place subject on double-sided tape on black slide
  2. Locate subject using the "spotlight" of the vertical illuminator, center subject in viewfinder
  3. Turn off vertical illuminator, turn on ring light
  4. Turn on WeMacro Micromate stepper unit
  5. Set beginning and end of the stack via WeMacro app, run the stepper routine (stepping and shutter actuation)
  6. Move images from SD to computer
  7. Load images into Lightroom album
  8. Adjust a single image, then copy and apply to all images in the stack
  9. Export all to .TIFF
  10. Load exported images into stacking program (Zerene or Helicon, I use both and see which one is better)
  11. Save image, load into Lightroom
  12. Apply any final adjustments, export .JPG for sharing/posting/etc

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#13 Post by Jose Antonio Mena » Wed Mar 29, 2023 6:42 pm

Hi Again

I attach some pics about the DF epi iluminator system; as you can see, it has the same object of your "ligth ring", but it is included in the objective, well adjusted, and you needn´t working distance to install the ring.

In second hand market it musn´t be expensive; My epiiluminator plus the nosepiece with 4 BD objectives cost me about 200 Euros. For olympus must be symilar system. And you can combine the episcopic ilumination, with diascopic for the surrondings of the micrometeorite.

Regards

JA
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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#14 Post by Jose Antonio Mena » Wed Mar 29, 2023 6:44 pm

Thanks very much

And How and were do you find the micrometeorites?

Nice work

JA

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#15 Post by Scarodactyl » Wed Mar 29, 2023 11:12 pm

Epi brightfield improves somewhat at higher NAs imo.
It might be worth experimenting mixing with your ring light/epi darkfield illumination.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#16 Post by woyjwjl » Thu Mar 30, 2023 2:22 am

I'm curious. Since you have a complete BH vertical lighting configuration, why not buy the LWD NEOSPlan 100X?


I think it has a good cost performance ratio. What's the problem code?
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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#17 Post by heyitsmedusty » Thu Mar 30, 2023 2:50 am

woyjwjl wrote:
Thu Mar 30, 2023 2:22 am
I'm curious. Since you have a complete BH vertical lighting configuration, why not buy the LWD NEOSPlan 100X?


I think it has a good cost performance ratio. What's the problem code?
Yeah I probably shouldn't have made the upper limit so high. At that magnification, you can't image the whole subject for a portrait style image. I do have a 100x MSPlan (not LWD) that I use for closeups of features though, and I do use the vertical illuminator in that case.

The highest magnification objective I can use for my smallest micrometeorites is around 80x, and they fill the sensor. I do have the ULWD MSPlan 80x, but it is producing somewhat soft images. I'm still experimenting with it quite a bit though, as there could be something in my light setup that needs to be improved to sharpen things up.

Regardless, I'm just looking for suggestions on the best objectives in this range that have long working distances and high n.a. so I can know my full list of candidates to consider.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#18 Post by woyjwjl » Thu Mar 30, 2023 7:44 am

It is recommended that you use DIY LED lighting for vertical lighting systems, which is not expensive.

The reason for saying this is because the second-hand vertical lighting system I purchased includes this. (It is estimated that the original lighting system has aged.)

https://www.microbehunter.com/microscop ... 25&t=17616

Of course, I am not an expert in this area and cannot scientifically compare improved lighting systems. I hope you get what you want. This is an interesting area.

Best regards.
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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#19 Post by heyitsmedusty » Fri Mar 31, 2023 3:13 pm

woyjwjl wrote:
Thu Mar 30, 2023 7:44 am
It is recommended that you use DIY LED lighting for vertical lighting systems, which is not expensive.
The lighting I use in my vertical illumination system is actually DIY. It's a high-powered COB LED that greatly outperforms the original halogen light box, which produces a VERY warm temperature light.

My light ring is basically a tube with a couple strips of LED light strips soldered together around a diffuser. It is pressure-fit around the objective, positioned high on the objective to swing into place, and then lowered once the objective is locked in.

I have done quite a few iterations, here are some examples of a recent one:

lighthood-1.jpg
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lighthood-2.jpg
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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#20 Post by Sure Squintsalot » Fri Mar 31, 2023 3:46 pm

Nice.... I have a few adapters as well made from Sch. 40 PVC.

Where would microscopists be without Home Depot!

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#21 Post by zzffnn » Fri Mar 31, 2023 3:56 pm

heyitsmedusty, I am interested in learning more about your lighting techniques.

You have posted two micro meteorite photos. You indicated that the second photo was taken with vertical illuminator, which you do not prefer for photography. The first photo seems to he produced by your DIY LED ring light (which you prefer for photography)? Please correct me if I am wrong.

Obviously, those two photos are of two very different meteorites and not directly comparable. Different micro meteorite may require different lighting techniques.

To my eyes though, the second image looks more natural; you can tame the reflection further with polarizers, if you want.

The first photo has so much reflection that my eyes/brain cannot make out what the actual meteorite looks like. Is that what you really prefer?

I think what renowned microphotographer Charles Krebs usually does with shiny subjects is a ping pong ball kind of diffusion dome, then shine 3 xenon speedlite snoot lights onto the dome. So from the micro meteorite point of view, the light source would be the ping pong ball diffusion, not the reflection image of LED rings or objective metal outer shell.

I do realize that it is very difficult to construct a ping pong ball diffusion to suit such a small micro meteorite. In theory, the closer your diffusion material or light source to your subject, the better (softer) looking the lighting is. So that means the ideal diffusion dome size would be only slightly bigger than the micro meteorite itself (to get really close to the meteorite), which is nearly impossible to do for amateur microscopists.

Please do not take this as a personal challenge or insult. I have examined bigger micro meteorites before at 40x NA 0.55 and know that they are quite difficult to photograph well; especially those spherical glassy balls such as the one in your first photo. I don’t know how to image such difficult subjects; so I am interested in learning more from you.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#22 Post by heyitsmedusty » Mon Apr 03, 2023 6:19 pm

zzffnn wrote:
Fri Mar 31, 2023 3:56 pm
heyitsmedusty, I am interested in learning more about your lighting techniques.

You have posted two micro meteorite photos. You indicated that the second photo was taken with vertical illuminator, which you do not prefer for photography. The first photo seems to he produced by your DIY LED ring light (which you prefer for photography)? Please correct me if I am wrong.

Obviously, those two photos are of two very different meteorites and not directly comparable. Different micro meteorite may require different lighting techniques.

To my eyes though, the second image looks more natural; you can tame the reflection further with polarizers, if you want.

The first photo has so much reflection that my eyes/brain cannot make out what the actual meteorite looks like. Is that what you really prefer?

I think what renowned microphotographer Charles Krebs usually does with shiny subjects is a ping pong ball kind of diffusion dome, then shine 3 xenon speedlite snoot lights onto the dome. So from the micro meteorite point of view, the light source would be the ping pong ball diffusion, not the reflection image of LED rings or objective metal outer shell.

I do realize that it is very difficult to construct a ping pong ball diffusion to suit such a small micro meteorite. In theory, the closer your diffusion material or light source to your subject, the better (softer) looking the lighting is. So that means the ideal diffusion dome size would be only slightly bigger than the micro meteorite itself (to get really close to the meteorite), which is nearly impossible to do for amateur microscopists.

Please do not take this as a personal challenge or insult. I have examined bigger micro meteorites before at 40x NA 0.55 and know that they are quite difficult to photograph well; especially those spherical glassy balls such as the one in your first photo. I don’t know how to image such difficult subjects; so I am interested in learning more from you.
The top micrometeorite photographers in the world have many images you can take a look at here:
https://projectstardust.xyz/2022/10/27/ ... eteorites/

Poke around, and take a look at their very reflective glass type MMs to get an idea of the lighting setup they use. You can see their light rings in the most reflective ones, which I think is actually a very nice look. My solution to the lighting problem is vastly different from theirs, but yes I do prefer the look of the first image in this string to the second one. It's also important to note that they are VERY different textures to photograph. Here is another photo using the exact same lighting setup, where the "ring of light" is not reflected in the same way.


barred-small.jpg
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As for diffusion, my most recent light ring device is very well diffused. Here is the current one, along with the objective "cap" I use to get more top-down light onto the subject (different ones printed to fit on each objective) --

lightring-1.jpg
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lightring-2.jpg
lightring-2.jpg (111.39 KiB) Viewed 3253 times


I'm pretty happy with my light setup, which is why I wanted to consider what objectives exist out there with very long working distances and very high n.a., and are calibrated to work without coverslips or immersion.

Hope this helps!

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#23 Post by zzffnn » Mon Apr 03, 2023 8:02 pm

Thanks, your current implementation does look more diffused .

Have you thought about shinning light sideways around the horizontal perimeter of those glassy spherical micro meteorites, through 3D printed diffusion balls of different sizes placed on stage, instead of diffusion light from above? This may tame most of the “hot” reflections.

I know you may personally prefer the very first photo of this thread and that we probably have different esthetic preferences. Some times, “hot” reflections in one person’s eyes may be another person’s interesting highlight.

To my eyes, I prefer peripheral soft light (as mentioned above) or a single narrow ring, like those in published micro meteorite works (and in spider eye balls), instead of several wide “hot” rings.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#24 Post by Phill Brown » Mon Apr 03, 2023 8:17 pm

I don't have any way of more than 0.3mm F.O.V and more than x40 objective.
By the time I get to 100x with 3.2 WD it's down to about 0.1 or there about.
That may or may not be helpful.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#25 Post by woyjwjl » Tue Apr 04, 2023 1:46 am

No, it exists.
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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#26 Post by heyitsmedusty » Tue Apr 04, 2023 2:07 pm

zzffnn wrote:
Mon Apr 03, 2023 8:02 pm
Have you thought about shinning light sideways around the horizontal perimeter of those glassy spherical micro meteorites, through 3D printed diffusion balls of different sizes placed on stage, instead of diffusion light from above? This may tame most of the “hot” reflections.
The light is already coming in sideways around the horizontal perimeter, as the path into the subject is very narrow. The "hard" vs "soft" look (if you're referring to the sharp drop-off from the light ring reflection to the dark circle in the very reflective MMs) is more a symptom of the objective lens being very close to the reflective surface, thus reflecting the large black lens in the mirror surface. The further away the lens is, the smaller that circle is reflected back, and more "diffuse" the light looks.

This is why I'm looking for the longest working distance objectives with high n.a., to minimize that lens reflection. Even the very best MM photographers in the world suffer from it, so it can't be totally eliminated. But with enough space built in, at least more light can get in to expose detail on the surface.

Check out what I mean here:
https://projectstardust.xyz/2023/01/12/ ... -nmm-4018/

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#27 Post by Phill Brown » Tue Apr 04, 2023 3:11 pm

I pulled an ∞/1.2mm 40x .60 PL L from inverted, cleaned it and put in ∞ iscope to test.
It's not a happy bunny in there.
Just about the worst resolution of anything I've tried including oil objective dry.
I can't say I know what I'm doing with the combination though, tried turning the slide upside down to check if that was the issue, just be aware that it might not work just because it's ∞ and the threads are right.
Someone here should be able to say why I needn't have bothered because it was never going to work.
I need to use a LWD condenser with it, it's not compatible ect.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#28 Post by heyitsmedusty » Wed Apr 05, 2023 3:05 pm

Phill Brown wrote:
Tue Apr 04, 2023 3:11 pm
I pulled an ∞/1.2mm 40x .60 PL L from inverted, cleaned it and put in ∞ iscope to test.
It's not a happy bunny in there.
Just about the worst resolution of anything I've tried including oil objective dry.
I can't say I know what I'm doing with the combination though, tried turning the slide upside down to check if that was the issue, just be aware that it might not work just because it's ∞ and the threads are right.
Someone here should be able to say why I needn't have bothered because it was never going to work.
I need to use a LWD condenser with it, it's not compatible ect.
Phill, is that objective marked to be used as phase contrast low (PL), meaning it has a phase plate within the objective and should be used with a special condenser annulus? The phase plate will reduce your total n.a. (since it blocks light).

More info here:
https://www.microscopyu.com/techniques/ ... microscopy

I'm specifically looking for objectives which are meant to be used with reflected light, and as far as I am aware you would never use a phase contrast objective without a condenser.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#29 Post by Phill Brown » Wed Apr 05, 2023 5:12 pm

It is that. PL PH L.1.2mm corrected.
The phase alone rarely causes anything like that much of an issue on its own.
The combination is especially useless.
Old oil on a dry objective sort of bad.

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Re: Recommendations for 40x-100x Objective, LWD, High n.a.?

#30 Post by ADi » Sat May 20, 2023 3:01 pm

Hi,
I use Neo SPlan 80x / 0.75 ULWD with TL=100mm for 45x and TL=200mm for 80X.
Best, ADi

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