Your Favourite Objective.

[apochronaut]

I don't know whether this is if interest to anyone but how about piping up about your favourite objective lens? The one that is effortless and a joy use and always exceeds expectations. Two or three is even o.k. Sometimes a whole series might be in order. Maybe don't go over 4.

[Microscopy_is_fun]

I really like the Leica HC PL Fluotar series of objectives. There is a large market for used lenses, so you can buy them at somehow reasonable prices. Their color rendition is excellent in my view, and they work flawlessly in brightfield, DIC and fluorescence.

[imkap]

I like my Olympus Splan 20...

[Wes]

I really like the multi immersion PLAN-Neofluars from Zeiss. Mainly because water immersion removes spherical aberration in water embedded sample, much more so than oil immersion. And I mostly look at protists so this is ideal.

[zzffnn]

My favorite would be an 160TL water iris plan apo of ~50x-60x NA 0.6-1.1 strain free for DIC, darkfield and COL. Because of what Wes stated.

It probably exists but I haven’t found one at good price.

I do have a few that are close enough:

1) LOMO water apo 65x 1.1 without iris;
2) many brands produced oil iris at 40x-50x

[apochronaut]

I really like the multi immersion PLAN-Neofluars from Zeiss. Mainly because water immersion removes spherical aberration in water embedded sample, much more so than oil immersion. And I mostly look at protists so this is ideal.

Nice photo. Makes it look like a 10 meter monolith. Those have always intrigued me. I presume the principal is similar to a correction collar.
So you do therefore notice a difference in the image quality, depending on the r of the sample and the selection of immersion medium?

Someone needs to invent coverslips with an r of 1.33!! Glycerin compatible ones already are there but expensive, although not too bad from China.


Maybe cryolite would be a candidate. It is now synthesized from fluorite.

[Wes]

presume the principal is similar to a correction collar.

Exactly, not only you can select the immersion medium but you also have the option to select whether the sample has a coverslip or not.

So you do therefore notice a difference in the image quality, depending on the r of the sample and the selection of immersion medium?

I haven't formally tested this but in general I get the best contrast when I match the refractive index of the immersion medium to that of the sample. Have a look at this article that described the problem in more depth.



https://www.researchgate.net/publicatio ... berrations

[PeteM]

One that comes to mind is the Nikon CFI 20x Plan Apo often discussed here. A world class objective at an AmScope price. A wide flat field, best in class working distance, and with a 0.75 na it can be pushed to 750x.

I'd add that the 20x magnification is a favorite. It offers a wonderful combination of enough magnification to see many subjects (plant cells etc.) and enough depth of field to tolerate thicker specimens. Even cheap Chinese ones, while nowhere near the quality of the Nikon above, provide satisfying images. The old AO 20x plan achromat, the Olympus DPlan and SPlan 20x, the Nikon EPlan and CFN Plan 20x, the Zeiss Neofluar 16 or 25x -- all excellent in their price range.

Another is an entire category of objectives - the 60x Plan Apo oil immersion objective - when higher resolution is needed. I have finite examples in Nikon and Olympus (SPlanApo) and infinite examples in Leica HC, Nikon CFI, and Olympus UIS - all with DIC. They offer the the same high numerical aperture and resolution as their 100x plan apo brethren, but offer a bit more working distance under the cover slip. Since images will be captured and sized digitally, the 60x can be effectively a 100x or even a bit more. The Leica HC version is probably my favorite, though they're all spectacular. It has excellent contrast, a wide field of view (common to all the infinity versions), and a neat "lock up" feature to get it out of the way of dry objectives.

[apochronaut]

presume the principal is similar to a correction collar.

Exactly, not only you can select the immersion medium but you also have the option to select whether the sample has a coverslip or not.

So you do therefore notice a difference in the image quality, depending on the r of the sample and the selection of immersion medium?

I haven't formally tested this but in general I get the best contrast when I match the refractive index of the immersion medium to that of the sample. Have a look at this article that described the problem in more depth.



https://www.researchgate.net/publicatio ... berrations

So your link and diagrams indicate that the effect of a lack of an arrow straight ray distribution with an aqueous sample , using a glass coverslip is minimal?....not worth pursueing homogeneity?

[deBult]

Very fond of my Olympus SPlanApo 20* na 0.7 dry (actually have 2 in use on 2 different scopes), main area of use is watching algae and protists.

The 40* SPlanApo and the D Achromat 20* Negative High phase contrast are my second best.

The “simple” D Achromats have a Depth of Field/Focus advantage though.

[apochronaut]

I just repaired an S planapo 40X .95 with a correction collar( BF) for a forum member. The meniscus lens dropped out of it's cell. A chunky objective, although mostly in the barrel and collar. The construction of the actual lens packs in the moving column are a little flimsy in my opinion.
Performance was pretty good, I agree. Excellent contrast.

[apochronaut]

Over the years my microscopy has drifted towards the use of higher magnifications more frequently. I think that this is because as the objectives I have been able to own have become "cleaner" the ability to image small details has improved, so I search those details out : cilia, organelles, cellular components, hitch hikers, polymorphic forms. There is a lot out there at ultra microscopy levels. I also search out objectives that can image those details.
I still use a 40 year old 100 watt Research Balplan but probably wouldn't be anywhere near as much, if it weren't for the 125X 1.4 N.A. Flat Field Apochromat that only works in a Balplan or Flat Field Dynoptic/Dynazoom. It has an unusual quality ; that of a noticeable greater depth of field than other oil immersion high power objectives I have used, irregardless of colour correction or N.A. It was designed by George Aklin at Bausch & Lomb in the 1970's sometime. Something like a beating Rotifer mastax for instance becomes an intricately defined, colourless, giant organelle at 1250X, rather than a roughly structured technicolour pulsing mass. It also works so well with it's Flat Field Apochromat mates. A jewel. The 25X .65 in the same series goes toe to toe with the Reichert 25X .65 planapo which isno small feat. Both are the most utilitarian medium low power dry objectives I have used working just as well at 375X as at 250X.
A couple of others that bear mentioning are the AO 40X .80 planapo made for the 34mm parfocal system and the AO/Reichert 40X .70 planfluor made for the series 400 microscopes. The 40X .80 outperforms some 40X .95 planapos I have used and the 40X .70 planfluor is a distinct overachiever. It's modest N.A. belies a remarkable imaging capability, while at the same time being indicative of it's flexibility when it comes to coverglass thickness and w.d. At 600X it is just as good but yet again with superior w.d., probably the reason they lollygagged on releasing a 60X.

[Alexander]

My favorite objective depends on the application.

For fluorescence work my favorites are 10/0.45 oil and 40/1.3 oil.

For protists water immersion is what I want. My favorite one is a 25/0.65 W.

On an inversed scope I want long working distance and the ability to look through glass up to 1.3 mm. Got a good selection for the job.

There is no objective that works best for everything.

[Scarodactyl]

It's so hard to pick. The 20x nikon apo was my first taste of high NA and magnification and that has defined a lot of my subsequent workand I still use it a fair amount. My unbranded 40x water immersion apo lets me see things inside gems none of my other objectives can and I like that it's a custom job with serial number 002. I'm unlikely to ever see another one of those. A recent surprise is my Optem 2.5x, which appears to just be a single doublet. It has lots of field curvature but tons of working distsncr a sharp, high resolution image with little CA, way better than my mitutoyo 2x except in planarity. That's another oddball with little info available--optem just said they don't make it anymore.

[BramHuntingNematodes]

That 47.5x b&l apo na .95 w/ collar it was so hard to find a good one and tricky to use I can't help but savor the image it gives

[tlansing]

Hi Wes,
I was interested in your comments about the Plan Neofluar multi-immersion objectives from Zeiss. I know you use your Zeiss PM III for DIC microscopy and was wondering if your DIC system uses individual sliders for each objective or whether you have the first Zeiss DIC system with a condenser with Wollaston prisms and a single analyzer/combiner. From what I understand, the original system used plan achromats of specific serial numbers but also that neofluars (which I use for the higher NA) work fine as well. I am wondering if one of these plan neofluars would work with the original Zeiss system. Would you have any insight into this?
Tim

[Wes]

So your link and diagrams indicate that the effect of a lack of an arrow straight ray distribution with an aqueous sample , using a glass coverslip is minimal?....not worth pursueing homogeneity?

From what I understand the difference in refractive index between oil+coverslip (n=1.55) and water (n=1.33) causes the large-angle rays to focus at a different height relative to rays with smaller angles i.e. spherical aberration. With water immersion the light refracts twice, once at the water-coverslip interface and then once again at the coverslip-water immersion interface so you can achieve good focus even deep in the aqueous sample.

Hi Wes,
I was interested in your comments about the Plan Neofluar multi-immersion objectives from Zeiss. I know you use your Zeiss PM III for DIC microscopy and was wondering if your DIC system uses individual sliders for each objective or whether you have the first Zeiss DIC system with a condenser with Wollaston prisms and a single analyzer/combiner. From what I understand, the original system used plan achromats of specific serial numbers but also that neofluars (which I use for the higher NA) work fine as well. I am wondering if one of these plan neofluars would work with the original Zeiss system. Would you have any insight into this?
Tim

Hi Tim,
I use the DIC system with individual sliders. I honestly have no idea whether these plan-neofluars would work with the old DIC system. Asking our friends over at the German microscopy forum might provide an answer.

[houstontx]

leitz 50x npl fluotar oel 1.0 160mm 0.17mm...amazing on a reichert zetopan dik. never got to try w leitz ict

oly splan apo 20x 160mm

oly planapo 40x 0.95 correction bx infinity

nikon plan apo 40x corr 0.95

i would love to that gly imm obj! clean up w dist water a big plus

[Rossf]

I’ve got way too many objectives to easily pin down but for simple achromats I really like the short barrel Leitz 25x .5 and 45x .65-the 45x in particular with just a bit more mag but bit more depth of focus that usually quickly goes once you jump from 20x to 40x…oh and my Leitz 13x .4-again less common magnification and really sharp-planarity drops quickly which can help the right specimen jump out from the surrounding flotsam..

[apochronaut]

A 13X .40. I never saw one of those but it sounds like a jewel, especially at a very useful 13X magnification. It would easily handle a 15X eyepiece and since they have a real field of more than 1.5X that of a 10X, a 13X under such an N.A. umbrella would act like an ultra wide field 20X with no resolution loss, and with a lot of w.d.. A .40 N.A. is the equivalent of a 20X having an N.A. of around .54, which is pretty good!

[patta]

After a lot of thinking, here's my favorite - a 100x oil from about 1930. It even works, but I don't use it due to fear of damaging it (no spring mount..)
.

[Wes]

I am wondering if one of these plan neofluars would work with the original Zeiss system. Would you have any insight into this?

I asked someone who has the old DIC system and the 40/0.9 plan-neofluar and they told me it doesn't work particularly well. On the other hand the 25/0.8 plan-neo apparently works very well with the old system.

[apochronaut]

After a lot of thinking, here's my favorite - a 100x oil from about 1930. It even works, but I don't use it due to fear of damaging it (no spring mount..)
.

I am sure that is a nice objective. Koristka products, certainly were beautifully made. I have a companion objective to that one from roughly the same era : black base and c.o.b. barrel. The previous Koristka production were all lacquered brass. Mine is in a lacquered brass cannister, rather than paint on brass. Marked ser. #26171 parallel to the axis along the side.
F. Koristka Milano - Italy around the bottom of the barrel.
1/15" IMM. ACQUA AP. N 1.20 around the top.

Fratelli Koristka was acquired by Officine Galileo in 1929, so your objective is likely as you say 1930's and my example slightly prior.

[apochronaut]

After a lot of thinking, here's my favorite - a 100x oil from about 1930. It even works, but I don't use it due to fear of damaging it (no spring mount..)
.

I am sure that is a nice objective. Koristka products, certainly were beautifully made. I have a companion objective to that one from roughly the same era : black base and c.o.b. barrel. The previous Koristka production were all lacquered brass. Mine is in a lacquered brass cannister, rather than paint on brass. Marked ser. #26171 parallel to the axis along the side.
F. Koristka Milano - Italy around the bottom of the barrel.
1/15" IMM. ACQUA AP. N 1.20 around the top.

Fratelli Koristka was acquired by Officine Galileo in 1929, so your objective is likely as you say 1930's and my example slightly prior.

[Hobbyst46]

On the other hand the 25/0.8 plan-neo apparently works very well with the old system.

Indeed, my 25x0.8 multi-immersion Plan-Neofluar works great on my old Zeiss West.

[tlansing]

Hi Wes and Hobbyst46, thanks for the information. Might have to look for one of these. Wes, I did post an inquiry on the German microscopy forum and was basically informed that these plan Neofluars work only with the sliders for each objective, as in your newer Zeiss equipment.

[Wes]

Hi Wes and Hobbyst46, thanks for the information. Might have to look for one of these. Wes, I did post an inquiry on the German microscopy forum and was basically informed that these plan Neofluars work only with the sliders for each objective, as in your newer Zeiss equipment.

Could you provide the link? I'm always curious about the possible DIC prism-objective combinations.

[tlansing]

Hi Wes, not much information but here is the link: https://mikroskopie-forum.at/forum/inde ... et-werden/

Tim