New infinity corrected water immersion 100X objectives have arrived..

[apochronaut]

Just a heads up.

I have arranged for production of three versions of planachro water immersion objectives by a factory in China. They are being manufactured as you read this.

For now, there are 3 versions available. :
100X planachro 1.10 Water Immersion M25 60mm parfocal, infinity corrected, 200mm reference length, such as would work on Nikon E200 etc.
100X planachro 1.10 Water Immersion R.M.S. 45mm parfocal , infinity corrected, 200mm reference length, such as would work on Nikon E100 etc.
100X planachro 1.15 Water Immersion R.M.S. 45mm parfocal , infinity corrected , 180mm reference length, such as would work on Olympus.

These will be sold on ebay but for members of this forum , I will offer a 30.00 discount on each objective. Factoring in customs stepping all over them, it looks like the 200mm versions will be 245.00 U.S. ea. forum price and the 180mm versions will be 195.00. They should be available in about 2 weeks.

[Hobbyst46]

Best of luck !
For those that are not quite aware of the advantages of water immersion (me, being "addicted" to oil immersion...), would you elaborate a little about it ?

[apochronaut]

Thanks!
I use oil immersion a lot too. I have been fortunate enough to be able to secure high N.A. more highly colour corrected oil objectives in the past, when they were more available and not too expensive but I often find that I cannot make use of these high apertures with aqueous samples, and frequently do not immerse the condenser by choice, limiting the aperture down to about 1.15 or so.

I do have some water immersion objectives that I use in a 160mm AO series 4 ( Lomo, Baker, Koristka) and have found them superior for aqueous samples much of the time.

The principle of oil immersion is based on homogeneity of the elements between the condenser and the objective .
Many mounting materials are designed in order to bring the sample into a homogeneous state, with an n of around 1.52. However, with live aqueous subjects this isn't possible because the n of the sample is 1.33. Moreso, if the sample is thicker, the proportion of low n to homogenous n material in the sample is higher and a resolution reduction occurs due to spherical aberration, despite the N.A. of the objective being high.
It may seem counter intuitive but a higher resolution image can occur with a 1.15 water immersion objective than a 1.30 or even higher oil immersion objective under many circumstances with aqueous samples .

Infinity corrected water immersion objectives are prohibitively expensive from the big 4 manufacturers and used ones almost non - existant. For my AO/Reichert Diastar, I have never seen a cover slip corrected version of one. The closest I have come is a 63X 1.0 glycerin immersion.
This is an opportunity to provide good to excellent quality infinity corrected water immersion objectives to many users of some of the more economically priced infinity scopes out there. They will also work to upgrade the many Chinese infinity scopes there are , most of which are based on an Olympus pattern.

They also are obviously more convenient to use and might help encourage those that shy away from immersion microscopy due to the oil required.

[BramHuntingNematodes]

Incredible! Well done.

[Scarodactyl]

Cool! I don't know that I will need one but I love that you're doing this.

[abednego1995]

Very interesting, and awesome!
Are the objectives going to be corrected for 0.17mm coverslips or will they be just for dipping??

Cheers,
John

[Timor]

Nice work, apochronaut!
I often regret the lack of affordable, more 'interesting' lenses coming out of China.
I wonder if the Olympus version would work to any extent on an AO 120 infinity stand (not parfocal of course)?

Tim

[apochronaut]

Very interesting, and awesome!
Are the objectives going to be corrected for 0.17mm coverslips or will they be just for dipping??

Cheers,
John

They are all cover slip corrected at .17. I have mentioned a few times that there is this other level of production in China for a more professional domestic market. These objectives are on the back burner there as are some others. The designs exist but they are not generally produced. Production has to be arranged. So too of planapos.. Who knew?
They aren't cheap but in the range of 1/4 the cost of similar from the big 4.

[apochronaut]

Nice work, apochronaut!
I often regret the lack of affordable, more 'interesting' lenses coming out of China.
I wonder if the Olympus version would work to any extent on an AO 120 infinity stand (not parfocal of course)?

Tim

Probably not but I have not trialled any of them in the AO 34mm system.
A possible option there would be to convert the stand to 45mm parfocal with a series 400 head. There is plenty of room. If your nosepiece is already populated with some fancy stuff like phase or a 1014 , 1016 , 1303 , or you just love it anyway and a full scale conversion would be a big loss, what I have done is replace 2 of the hex grub screws with two thumbscrews and you have a quick change nosepiece. On a series 20, I have a planachro dark phase nosepiece and another 5 hole with 10X planapo, 20X planachro, 40X planapo, 50X iris oil planachro and 100 X iris oil planachro for DF.
Once changed a couple of times any minor alignment becomes second nature.
In your case a second nosepiece could have the water immersion plus some other Olympus or Reichert 45mm objectives of consequence. You would need the second head. Granted there is some expense but the microscope would be a beast and in the world of upgrading a scope, hard to beat.

Interestingly, for one of the research models the Chinese designers opted for a dovetail for the head of 50 to 51mm. AO used 2", which is 50.4mm. There is a tilting ergonomic trinocular head with a 26mm f.o.v. that will fit any AO stand and for 1/2 the price a standard 26mm f.o.v. trinoc.

[Zuul]

There is a tilting ergonomic trinocular head with a 26mm f.o.v. that will fit any AO stand and for 1/2 the price a standard 26mm f.o.v. trinoc.

Care to point to this? More curiosity than burning need, but it never hurts to window shop. I also have friends in China, which can be helpful on occasion.

Would you recommend the 180mm “Olympus” version of the H2O immersion lens for use on a 410?

[Timor]

what I have done is replace 2 of the hex grub screws with two thumbscrews and you have a quick change nosepiece.

Thanks Phil, lots of food for thought there.
Any idea of the thread size of those screws? I've not had much luck so far replacing AO screws.
Please PM me if you'd rather not derail this thread too much.
And like Zuul, I'd be interested in seeing the trinocular head

[apochronaut]

There is a tilting ergonomic trinocular head with a 26mm f.o.v. that will fit any AO stand and for 1/2 the price a standard 26mm f.o.v. trinoc.

Care to point to this? More curiosity than burning need, but it never hurts to window shop. I also have friends in China, which can be helpful on occasion.

Would you recommend the 180mm “Olympus” version of the H2O immersion lens for use on a 410?

That would be my impression at this point but when I get them all here, I can do a comparative assessment. Lead time for delivery is supposed to be about 3 weeks and 1 1/2 have elapsed. Have to wait until arrival.

The ticket on those S.W.F. trinocular heads without eyepieces is around 1200.00 for the ergonomic and 525.00 for the conventional at a retail level, so for what one is getting not too bad since they are brand new . Less if you can get them direct. They are a 3 postion trinocular too.
The eyepieces are corrected to be used with the NIS60 (60mm parfocal) objectives that mimic the Nikon system and they are about 300.00/pr. For sure on those, you can do a lot better on ebay and matching occulars to any intended system is important.
One of those heads would have to be tested in a series 400. I could see the AO/Reichert or Reichert Austria 45mm objectives in a Microstar or Diastar with a pair of Polyvar 30mm tube eyepieces being quite the microscope. That would give you a 24mm fov.
I am not sure what the corrected image circle would be with the more advanced earlier 34mm planachros but I doubt if they would support much more than 22mm.

Unfortunately I don't have any better images of those heads than the ones featured in the brochure for the microscope they are intended to be used on, which had 22mm, 26mm and 25mm ergonomic options.(25 not 26mm)

https://www.bestscope.net/bs-2081-resea ... icroscope/

[hans]

What is the working distance of these?

[apochronaut]

What is the working distance of these?

The 180mm reference length version is .19mm and the 200mm are .20.

[hans]

Thanks, I think I understand now what you were saying about homogeneity and why, if there is going to be water under a cover slip, it can be better to have water (instead of oil) on top also. But what are the advantages of cover slip correction vs. "dipping" like John mentioned? Is the cover slip just needed as a barrier to keep the specimen from drifting/swimming away? Or are there other reasons to use one?

[apochronaut]

b_
Thanks, I think I understand now what you were saying about homogeneity and why, if there is going to be water under a cover slip, it can be better to have water (instead of oil) on top also. But what are the advantages of cover slip correction vs. "dipping" like John mentioned? Is the cover slip just needed as a barrier to keep the specimen from drifting/swimming away? Or are there other reasons to use one?

Dipping has been used quite a bit historically but there are practical limitations to dipping. There were stereomicroscope dipping objectives going back into the 20's at least but the disturbance of the sample can be great as the magnification goes up.
Various dipping objectives exist now for use in situ for tissues but they are not really high magnification usually. A more common design for high magnification and resolution is to use water immersion as a replacement for oil, spread on top of a cover slip.
Low n.a. covers would probably improve the homogeneity somewhat. Typically , for glycerin immersion quartz covers are used, which are very close to the refractive index of glycerin. High grade optical plastic covers may be just the cat's meow for water.

'

[hans]

Makes sense, so the reason to choose 0.17 mm glass specifically is basically the same as for dry objectives -- already standardized and widely available?

[Scarodactyl]

Most of the time you won't want to go straight to a 100x immersion objective anyway. You probably need to be able to examine your sample with your other objectives too and they're probably corrected for a .16 cover slip as well.

[apochronaut]

Yes, so the W.I. objective allows a little more flexibility with high dry objectives, since the immersion medium is so easily removed.
Theoretically, an oil immersion objective with a higher N.A. will provide superior resolution only when the detail(s) being examined are at or very close to the cover slip. As one looks down through the sample and certainly where much of the areas of interest lie on the slide, the W.I. maintains it's contrast and resolution whereas the O.I. undergoes a continuum of diminishment, as you look down through the water column.
I would have to say, a 40X or 60X W.I., at around 1.0 would be very nice.....

[apochronaut]

These objectives have arrived and my preliminary assessment of them is very good.
I will be thoroughly testing each one, one by one and communicate my accumulated findings, with supporting images.

[patta]

Congratulations!

There were stereomicroscope dipping objectives going back into the 20's at least

I was recently dreaming about a water dipping add-on lens, like 2x, for stereomicroscope.. maybe in near future. Your special order is very encouraging! What was the minumum order they asked for?

[apochronaut]

Five but the shipping gets increasingly attractive the more there are.These are high resolution cover slip corrected.
There were some older stereo scopes with water dipping objectives. Spencer had one back in the 20's , Bsker too.

[patta]

Five is great, I was expecting that you had to order a 1000 of them..
I desire your new jewels but decided that no, I don't have an infinity stand, it's no point! I'll try to stay content with old water Lomos and misused oil objectives.

The water immersion stereos, I believe you, but couldn't find anything on the net. Only thing is for new Leica, they offer objectives for stereo corrected for thick water mount (but no immersion).

[hans]

Five is great, I was expecting that you had to order a 1000 of them.

Yeah, 5 seems very low even if the design is already complete. Maybe they share many elements with other objectives that are in production, and the differences are mainly in assembly, like the positioning/spacing of the elements?

[apochronaut]

It's a little difficult dealing with that planned economy. I did it a little in the late 80's and not too much has changed. It seems unfair to call it subterfuge but they aren't exactly forthcoming when it comes to how they are providing the services that you ask.
The Olympus format objectives clearly came from a different factory than the RMS and M25 Nikon format objectives. I think the factory I am dealing with is the maker of the Nikon format objectives and they had to wait for the Olympus format objectives to be shipped . Factory 12 to factory 5. We require 5 units of #647 immediately.

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The Nikon format objectives show every sign of possibly being recently assembled or even made. The Olympus format objectives are definitely new but examination with a stereo microscope reveals that they have either been a warehoused part or were assembled from warehoused parts.
That's o.k. The 200mm R.M.S. objectives look suspiciously like AO objectives and work pretty well on a series 400. Not quite as good as 1.25 oil immersion but the water immersion sure is convenient and using an immersed condenser is weirdly more effective with the w.i. than the oil.