🔬 Should I buy a 60x dry objective instead of a 100x Oil? | Amateur Microscopy

A 60x dry (non-oil) objective can have several advantages over a 100x oil objective for general purpose applications.

Oil objectives require Immersion Oil for microscopy. The oil immersion objective is rotated into the oil (so that there is no air between the slide and the objective). This causes the objective and slide to be covered with oil and they must be cleaned.

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[davewinch]

A lot of people replace the 100X objective with a 60X. I just ordered mine, I'm sure I will get more use out of it.
More than once, I bumped my slide containing live specimens when switching to the 100X objective and messed up what I wanted to look at.

[Feynman.R]

I have been a naturalist for a long time, I mainly photograph insects and spiders, springtails. And recently I expanded my arsenal of naturalists by buying a microscope. As a newbie, I constantly have a lot of questions, and I almost always find the answer on your YouTube channel! You have a great channel, thank you very much for sharing your knowledge and experience with the whole world.

[ftunder]

A 100X oil would also need extremely thin and flat section, in the order of 5 micrometer, assuming you have a cellular structure small enough and with sufficient contrast, like a chromosome. That's something you can get with a professional microtome. I did some histology for research and I used to embed specimen in Paraplast wax. That alone was not obvious and required a dedicated machine for embedding in wax after a lot of tissue processing. Early on, the tissue was too dried and almost cooked in the wax which made cutting sections thinner than 5 or 8 micrometer very difficult. 10 micrometer is too thick in my opinion for 100X. After a lot of practice and in optimal conditions, I obtained 4 to 5 micrometer thick sections that I stained with the classical hematoxylin eosin method, but that step again proved to be critical. In short, to use the 100Xoil the tissue has to be perfectly fixed, perfectly dehydrated (not too much) and infiltrated with a solvant, then perfectly embedded in the best wax, perfectly sectioned at the thinnest possible thickness, perfectly stained to obtain the best contrast, and finally perfectly mounted with a dry mounting media. With a professional equipment well worth $100, 000, it took me thousands of hours of practice to cut slides to reach that level of perfection. I actually used the Oil objective a few times, contamination to other dry objectives occurred and that was enough to convince me it wasn't worth it. Perhaps you'd want the 100X oil only if you were able to cut sections trough hard plastic embedding media. These hard embedding media indeed allow to cut 0.5 to 2 micrometer thin sections but again you'd need top notch professional equipment and a lot of experience with embedding machines and microtomes. At this level you get a resolution intermediate between traditional histology and electron microscopy and indeed you may want the 100X oil in that case. Also, in the past with only argentic films and 24x36 cameras, it was difficult to focus and perhaps that was the reason people needed to over-magnify the tissue to 1000X in order to obtain a decent image, an image that would just barely look OK compared to today's CCD or cmos images at 400X.

[janvangastel]

I bought a 63 x objective for my Leitz orthoplan last year and now it's one of my most used objectives. The difference between the 40x and 63 time is big. I am very glad I bought it.

[Quercus]

You are probably right for the large majority of amateur microscopists, but not for for everyone. For example, I myself use my microscope (practically) only for mushroom identification and then a 100x oil objective is a necessity.

[TheMicroscopist-yf]

I am very happy with my Leica PL Fluotar 40x Oil Ph3 objective and DIC. But to be honest I rarely felt the need to go past this magnification. I choosed oil because it really gives crisp images for my demanding photographic needs. I rarely use the 20x, 10x and 5x.

As for the 100x Oil, no, I would not need that magnification for my hobby pond life photography/videography.

As for the cleaning, a single touch with a lens tissue soaked with 100% ethanol is enough to remove all the oil.

[michaelb.]

Your suggestions are right on - great video! The only comment I will add is that (budget permitting) a better quality 60 dry will be worth the cost. If you have a standard 40x with NA = 0.65 and go to 60x/0.80 objective you have increased magnification 1.5x but NA only increased 1.23x so this is why many people feel the 60x dry is never as sharp as 40x and don’t like it. The higher NA 60x objectives with NA of 0.95 will resolve this and can usually be found for a couple hundred dollars on eBay but at a minimum I prefer at least 60x with 0.85NA which are offered at amscope and others for less than $50 - the 60x dry is one area I usually find worthwhile to spend a little extra on

[marcotronic]

A 60x replacement for the 100x oil objective was the first thing I did when I recently got my first microscope.

[Rick-ttyq]

Great advice! I will keep my 100x oil but a 60x is an excellent alternative and much cleaner/easier! Thanks Oliver...you’re a gem!!

[lotharmayring]

ok, but a good infinity 40x can do the job also but it depends at what you want to look. If i see an object which is of interest i buy a REM electron microscoy picture for the object that costs me about 50 Euros

[inharmonywithearth]

Can somebody please tell me if I can put a Chinese 60x dry objective on my Zeiss microscope and if so what ones? The zeiss objectives are hundreds of dollars new and say "for parts only and broken" if a little less..

[ross]

Diatoms are the object of interest I bought the oil immersion lens for but then I got more interested in other plankton especially how they move and I got put off by all the faffing about involved with oil immersion. I like to jump from one subject to the next too I think oil immersion requires a lot of discipline and focus on one particular subject.

[WolfTheDog]

I just asked you this almost exact question. Thanks for pointing me to this video. You make very good points. The 100x sounds like it's really just a hassle to use.

[glasslinger]

I was wondering why there were so many 100x oil objectives cheap on ebay!

[davidskeet]

There are some advantages to be had when using OI objectives that were not discussed. The first is they give stunning images. The reason for this is they do not suffer from spherical aberration irrespective of the thickness of the coverglass. This is not the case with a high magnification, high NA dry objective that does not have a correction collar to mitigate the effects of spherical aberration. It's for this reason that I have traded my 40/0.8 dry plan apo with no correction collar for a 50/0.8 OI plan achro. I now get clear sharp mid-power images irrespective of coverslip thickness. There is a lot to be said for OI mid-power objectives. They can give some lovely images and are a favourite amongst diatomists I'm told. Regarding cleaning oil off objectives and slides. It's not a problem. I used mild detergent in distilled water and cotton pads. I inspect the front element of the objective for cleanliness by removing an eyepiece from the microscope, turning it back to front and use it as a loupe. Never use alcohol to clean oil off a lens as it can damage lens cements. For those with an aversion to using oil, you might like to try water immersion. Of course water can simply be blotted away. Very simple, and you will be rewarded with some stunning images. All the best.

[jessemangiardi]

is there any difference between 40x objective and 10x eyepiece OR 20x objective and 20x eyepiece if they both give 400x? Does a higher objective resolve the image better (I'm assuming the objectives are higher quality than the eyepieces?)?

[mkaufer]

I recently replaced my 100x oil objective with a 60x dry objective, and with the 25x eye piece the magnification is 1, 500 instead of 2, 000., not really a big difference and at 1, 500 Mag, I can view Bacteria with no problem, and besides anything past 1, 000 is harder to view anyway, so Im happy with my setup.

[inharmonywithearth]

The answer is YES! OF COURSE YOU SHOULD!

[teresashinkansen]

I use the oil objective quite frequently so i don't find it that difficult to use probably I just got used to work with it. I use it mostly when I look at bacteria or conidia, many times you can see texture on the conidia and might help with with ID, for example _Aspergillus niger_ conidia has a rough surface that many times look like pumpkins or sand tires for an ATV, _Aspergillus fumigatus_ has a very rough conidia and they look like spiky balls. Also sorry for "spamming" you with comments, i just discovered your channels and they are so great! i just like to share my experiences when i get excited about all this stuff.

[martinazivko]

And besides, 100x oil takes more work to set up and later clean up.