The new bargain: PL M 100 / 0.90 ∞

[Adalbert]

Hello everybody,

I would like to show you my new bargain M100 PL / 0.90.

According to the seller, this is a product of the company: Union Optical Microscope.
Does anyone know this lens and can say something about it?

I took a few wing scales on the fly.

The working distance seems to be smaller than 1mm and the objective needs a lot of light.

Best,
ADi

[seta666]

The stack does not look good, but it does not show any CA´s ..could work well.
Butterfly scales with NA0.9 is difficult, I already tried..

[Scarodactyl]

Union is one of those lesser known Japanese makers like Kyowa or Seiwa. They never made it big like Nikon or Olympus, and are mostly known in the states as a supplier of whitebox scopes for other brands (mostly Unitron's earlier Examet and inverted metallurgical offerings, as well as some Wesco offerings). When China became the go-to for whiteboxing their prescence in the states seems to have declined a lot but they're still in business, apparently still making the same models they did back when Unitron sold them. They do make an apochromatic line of metallurgical objectives as well, though how good they are is a mystery. I have one of their digital zoom microscopes but haven't gotten to properly test it yet.
The stack looks a bit odd to me texturally.

[rjlittlefield]

The stack looks a bit odd to me texturally.

I agree. I suspect it's suffering from the "squirms around laterally" problem, illustrated at viewtopic.php?p=149187#p149187 . That gets progressively worse at higher NA and more oblique illumination. The problem is especially bad with shiny subjects, so as seta666 notes, metallic butterfly scales are tough. Getting an accurate picture of those finely textured scales at NA 0.90 with around-the-lens illumination will be very difficult, maybe impossible. I think of the picture as a "work of art", suggesting reality but certainly not limited to it.

--Rik

[seta666]

Getting an accurate picture of those finely textured scales at NA 0.90 with around-the-lens illumination will be very difficult, maybe impossible.

So, what would be a better way to light them? those reflections make me crazy sometimes, I have abandoned projects because of the amount of retouching they needed

[rjlittlefield]

So, what would be a better way to light them? those reflections make me crazy sometimes, I have abandoned projects because of the amount of retouching they needed

First, let me define a goal. For me, an ideal solution would end up producing an image that looks "just like" what I can get at smaller NA, but with more resolution.

That done, I'd love to propose a solution.

Unfortunately I cannot do that, because I don't know one and don't even have any good ideas. Sometimes I can't even figure out the structure in my own head, based on what I can see. Through-the-lens illumination may help, but even with that a curved reflective surface can send the light back into just a part of the aperture, potentially a small part, far off center, and then that part of the reflective surface will appear to move as focus shifts. Illuminating in transmission -- sending light through the structure like a condenser on a microscope does -- seems to help a lot in terms of reducing the squigglies, but then it also eliminates the 3D modeling that I wanted in the first place.

I'm afraid that this regime may mark the start of the area where we really do have to stop using light and switch to SEMs or something similar that intrinsically works with a lot smaller cone angles. Or maybe stick with light but augment the lenses with digital holographic microscopy (DHM). On quick read, DHM has always seemed promising, but I've never dug very deep into it.

As a practical matter, abandoning certain projects seems like a fine solution!

--Rik

[seta666]

First, let me define a goal. For me, an ideal solution would end up producing an image that looks "just like" what I can get at smaller NA, but with more resolution.
That done, I'd love to propose a solution. Unfortunately I cannot do that, .......................

I thought you knew the trick .

With scales like these problem is the same as with omatidea; the wild inner reflections and out of focus areas; makes software crazy.

Maybe one day stacking software will learn how to differentiate between details and those reflections, maybe through machine learning, but until that day comes retouching from slabs or even individual shots is the only solution I know.

If there are different depth layers like with scales not even that works. Objectives that show strong CAs only make things worse. Good thing about this lens he showed us is it did not show CA´s, could work with some very thin and flat subjects.

[Adalbert]

Hi Javier,
Yes I know, it was a test only but I also noticed immediately that there is no CA at all.
I have never had anything like that until now
Best,
ADi

[Adalbert]

Hi Scarodactyl,
Thank you for the information about the manufacturer of the lens!
I used extremely long exposure time for this test photo. I'm sure that caused additional damage.
Next time I will try to use either a dot printed with the laser printer or a chip/wafer.
Best,
ADi

[Adalbert]

Hi Rik,
OK, I will use something else as the subject for the second test photo.
What would you recommend?
Best,
ADi

[Adalbert]

Hello Rik,

Many thanks for the tip about DHM.

So, you need several narrow-band lasers
and software for the numerical reconstruction of the phase distribution of the backscattered light wave
(from the interferometric recording).
Do you know such software?

Best,
ADi

[Adalbert]

Hi Javier,

could work with some very thin and flat subjects.

Do you have any idea what would work best for this?
Best,
ADi

[rjlittlefield]

Many thanks for the tip about DHM.
...Do you know such software?

No. Everything I know about DHM (plus a lot more) is in that Wikipedia article I linked.

I will use something else as the subject for the second test photo.
What would you recommend?

I have very little experience at large NA, specifically because the gain in resolution does not seem worth the rise in frustration.

With reflected light, NA 0.8 is the highest I have used. The best results I have gotten were for the textured cuticle of a Brown Marmorated Stink Bug, as shown at https://www.photomacrography.net/forum/ ... hp?t=40860 . That post includes a zoom-in sequence, so you can see exactly where the area I shot was.

--Rik

[seta666]

Even a butterfly wing is too deep for a NA0.95; I took this one with a BD Plan 100/0.95; sold it right after this shot
Everything comes out weird; maybe those lenses work well with flat unanimated things like semiconductors and such,

The BD plan 100/0.80 ELWD was ok to work with, but I do not own it anymore; I also own a LU plan 50/0.80 which is OK to work with but I am selling to fund my microscope project. Fastest lens I am keeping for my vertical set up is a nikon CF BD 40/0.65

[Adalbert]

Hello Rik,

the gain in resolution does not seem worth the rise in frustration.

Yes, I have already seen the pictures of the bug, of course.
Best,
ADi