Starting with identifying a decent microscope

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Amoeba
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Starting with identifying a decent microscope

#1 Post by Amoeba » Mon Nov 27, 2017 1:36 pm

Since I an mew here perhaps I should first provide a little background.

My primary interests are astronomy and electronics. However health issues have forced me to give up then former and I sold my telescopes a couple of years ago. My first microscope purchase was a Nikon SMZ1 which is up to 40x zoom and which I use for electronics, particularly working with boards that contain SMD components. One thing that I have learned is that there is nothing more frustrating than trying to work with a poor optical system. The Nikon SMZ1 is great for its intended purpose but with a magnification of 'only' x40 it is unsuitable for anything biological.

My daughter recently expressed an interest in things microscopic and I was able to get a Celestron 44362 Infiniview 160x 'digital microscope' off eBay for 35GBP plus postage as a starting point. Knowing the Celestron brand from the telescope world, I figured since the RRP was around 200GBP, this ought to be a reasonable quality instrument. How wrong I was! At best this should more properly be described as a magnifier. At 160x the magnification resembles approximately that of the x40 on my SMZ1, but the quality of the images produced is very poor. Lighting can be very uneven and there is a big gap from about halfway to full zoom where it just does not come into focus at all. The digital imaging is equally disappointing. Although it is capable of saving 5mp images to SSD, when hooked up to a computer over USB it produces only 640x480 images from its 5mp camera! The stage is plastic and wobbly. Although it did provide us with a bit of fun, I am glad that I did not pay anywhere near the RRP. It does produce fairly reasonable magnified views of objects at low magnifications but is certainly nowhere near powerful enough to view anything down to cellular level.

So this experience has led me here to ask for advice as to what I should be looking for. What brands have good optics, which ones should be avoided? How much should I be looking to spend on a used microscope? Are microscopes with mirrors to be avoided in favour of those with a light? Can webcams be used with an ordinary microscope? What magnifications are required to view cellular structures of plants and microscopic pond life?

I would have to add that having looked around eBay for a couple of weeks I find myself very skeptical about the claims made on some listing of 1000x and higher magnifications, especially on the cheap zoom type USB devices. if I'm going to spend a hundered or two I want to avoid ending up with another piece of junk!

UPDATE: I have just found this which answers a great many questions but any opinions would still be appreciated!
http://www.microscope-microscope.org/ba ... oscope.htm

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Re: Starting with identifying a decent microscope

#2 Post by apochronaut » Mon Nov 27, 2017 3:09 pm

your telescope experience will serve you in good stead mostly, when it comes to microscopes. Celestron, has produced some strictly hobby microscopes, primarily to make some extra cash from an existing dealer network.
Yes, beware of outlandish claims regarding the magnification potential claimed by cheaper instruments. However, 1000X is a perfectly reasonable expectation, if it is through a quality instrument. Theoretically, about 1500X is possible but your telescope experience should tell you that in such circumstances everything must be just so to achieve that, with peak resolution. In practice, most instruments need to stay below 1000x.

The key with microscope optics is to stay within certain boundaries, which can be determined by looking at the specifications on the optics. The easy rule is; the maximum allowable magnification of any eyepiece/objective combination is 1000X the N.A.(numerical aperture), which should always be stamped on any quality objective.

Since you are in the U.K. , and are interested in a second hand microscope, several of the better brands should be well represented on the second hand market; Leitz, Zeiss, Jena, Nikon, Olympus but you also have the additional possibility of a quality domestic brand; Beck, CTS, Cooke-Baker, Vickers or even Watson.

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Re: Starting with identifying a decent microscope

#3 Post by apochronaut » Mon Nov 27, 2017 3:34 pm

Regarding the question about mirror illumination compared to built in illumination. Neither is better than the other, except of course that a built in illuminator is more convenient. With a mirror, you will still need an additional remote illuminator. A good one with high wattage can be had quite cheaply and you will need to learn how to adjust and align it correctly. The in base illuminators work very similarily; there is usually a mirror hidden in the base and occasionally everything with those needs to be cleaned and adjusted as well. Built in illuminators can sometimes be affected by electronic problems whereas remote illuminators are usually direct from the mains, so are pretty impervious to electronic or electrical problems.


here are a few listings from ebay U.K. that look pretty good, although I have no idea what your budget is.
https://www.ebay.co.uk/itm/Leitz-Laborl ... SwmBhaEY2q

https://www.ebay.co.uk/itm/Zeiss-Micros ... Sw3v5YuCgp

https://www.ebay.co.uk/itm/Watson-Barne ... SwhVxaF0bf
Last edited by apochronaut on Mon Nov 27, 2017 4:50 pm, edited 1 time in total.

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Re: Starting with identifying a decent microscope

#4 Post by Amoeba » Mon Nov 27, 2017 3:46 pm

Thank you for explaining the issue with Celestron. That explains why the instrument feels like a toy!

Regarding magnification, doing a bit more reading I see that 1000x is indeed reasonable for a quality microscope (10x eyepiece with 100x objective lens) although not used that often it seems. The maximum allowable magnification rule is also interesting to note. I did wonder how much resolution one might loose if one changed the 10x eyepiece for 20x or 25x. You can only push telescope optics so far and I suspected the same must be true with microscope optics.

Thanks also for listing some of the brands. Zeiss, Leitz and Nikon are of course well known and quite expensive, perhaps a bit too rich for my pocket, but I will keep my eyes open. The Olympus ones I have seen for a reasonable price so far have all been field microscopes up to 400x with a mirror. I have also seen the odd Vickers, CTS and Beck, examples of the latter two brands were also usually vintage monocular with mirror type.

I am however still curious about brands like Brunel, David Harris, Optika, Lomo, Opax, Bresser etc. I am currently watching a Brunel SP60, retail around 400GPB but I have no idea of the reputation of the brand, but it does seem to have a few useful features.

The linked Watson is also of interest and I have added it to my watch list. Thanks. I haven't really given my budget sufficient thought although initially I wanted to ideally keep it below 100GBP. I am now beginning to think that for a good quality used instrument I might need to be prepared to spend quite a bit more. I think absolute maximum would have to be 200GPB though, and that would need to include the outlay for some slides etc.

UPDATE: The Brunel has now gone for 230GBP. Jumped from 135GBP in the last minute!
Last edited by Amoeba on Mon Nov 27, 2017 4:43 pm, edited 1 time in total.

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Re: Starting with identifying a decent microscope

#5 Post by apochronaut » Mon Nov 27, 2017 4:41 pm

Lomo is Russian. Generally, they are very good but the grease can dry out on the older ones, which requires some cleaning and re-lubing to rectify.

The only microscopes that were made over the last 40 years or so that were made in a factory owned and operated by the named company are American Optical( U.S.A.), Bausch & Lomb(U.S.A.), Kyowa(Japan), Carton(Japan), Zeiss Jena(East Germany), Carl Zeiss(West Germany) Zeiss( Germany), Meiji(Japan),Nikon(Japan), Olympus(Japan), Vickers(England), Watson(England), Leitz(Germany, Portugal), Leica(Germany,Austria,Switzerland,U.S.A.), Wild(Switzerland), PZO(Poland), Meopta(Czechoslovakia),IOR(Romania), Nachet(France), Will(Germany) , Hundt(Germany), Lomo( Russia). A few of them, I can't remember right now. Some companies built frames but bought optics, mainly in Germany.

Just about every other brand, which are almost legion, are either a stencil brand from Japan and in the last 25 years or so a stencil brand from Korea, China or India. Often, marketing agencies, distributorships or a large dealership will buy an off the shelf stencil brand and have it branded with the name of their dealership or distributorship. Optika claims to be made in Italy. Partially assembled in Italy, is more like it. The optics are clearly, Chinese in origin.
Carton Optical in Japan ,branded a lot of microscopes for export. up until the chinese took over from them. Kyowa, too but Japan has become too expensive to stencil brand anything economically. China has an enormous number of manufacturing and assembly plants, supplying all kinds of instruments, world wide. You hardly ever see the real name on an instrument, just names like Amscope, Omax, Brunel, Bresseur etc. Chinese microscope brochures are kind of cute. I have some in hand here . One from NOIF; Ningguang Optical Instrument Factory is a 20 page colour brochure. Each microscope has at least a 4 x 5 colour picture, with some a full 8 x 11. The microscopes are all nameless, known by number only, clearly indicating the callout to put any name you want on them. Another , China Ningbo Teaching Instrument Factory shows 14 pages of colour pictures with each, nameless and numbered. Jiangxi Phenix Optical Instrument Co.Ltd.(GROUP), shows 28 pages of nameless, numbered scopes.
Buying a stencil brand scope used, would be a bit of a crapshoot, given that they were bargain brands in the first place. If you are buying used, better to aim a little higher and choose one that can stand the test of time. If you are on a tight budget, that Watson, I linked to above looks promising for 100 quid + shipping.
Last edited by apochronaut on Mon Nov 27, 2017 5:13 pm, edited 1 time in total.

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Re: Starting with identifying a decent microscope

#6 Post by Amoeba » Mon Nov 27, 2017 4:56 pm

Thanks for the rundown on all those brands and the heads up on the Russian Lomo grease problem. There is a similar problem on some Chinese telescopes where the grease gets thick and gooey after a year or two and everything starts to stick and you have tom dismantle, clean and lubricate. You have also confirmed my suspicion about the stencil brands although I have not heard that term before. I had noticed a number of these brands (Bresser, Amscope, Brunel, Opteka, Optika etc) having almost identical models and the same model numbers. I am watching a couple of Leitz although I would not be surprised if the final bids shoot up well beyond my budget. One of them looks quite dirty but I think could be cleaned up so might go for a bit less. There is a Leitz from Germany for 275GBP, a bit beyond my budget and without a lamp. I might have tried to find a way to stretch it a bit, but as it is incomplete I'm not convinced its worthwhile. I am asking how critical it is to have the correct Leitz lamp? Will a third party one work with it? But for that kind of money I'm not sure i want a cobbled together solution.

In the meantime, I am looking at that Watson. I have messaged the seller with a question about the eyepieces. If they confirm that everything is OK then I might put in an offer.

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Re: Starting with identifying a decent microscope

#7 Post by apochronaut » Mon Nov 27, 2017 5:10 pm

The eyepieces are in the tray. I think he just didn't put them in. The scope will need some cleaning but it sounds like you are up to the task.

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Re: Starting with identifying a decent microscope

#8 Post by JimT » Mon Nov 27, 2017 5:54 pm

In addition to the excellent advice from Apochronaut check out this site's home page; http://www.microbehunter.com/. Good info for beginners and buying advice.

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Re: Starting with identifying a decent microscope

#9 Post by Crater Eddie » Mon Nov 27, 2017 5:57 pm

Since you mentioned LOMO I will say that their scopes and optics can be quite good, but you need to know what you are looking at and for. If you are looking for something that works out of the box without a lot of fiddling, I would recommend going with one of the other brands mentioned.
CE
Olympus BH-2 / BHTU
LOMO BIOLAM L-2-2
LOMO POLAM L-213 / BIOLAM L-211 hybrid
LOMO Multiscope (Biolam)
Cameras: Canon T3i, Olympus E-P1 MFT, Amscope 3mp USB

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Re: Starting with identifying a decent microscope

#10 Post by MicroBob » Mon Nov 27, 2017 8:15 pm

The mentioned real microscope makers of the more recent past all made quite good instruments. Each maker had it's own advantages or disadvantages, like the quality of the grease, mechanical simplicity to make overhauls easier, good availability of trinocular tubes and plan objectives.... Most had models that are less recommendable than others. From all models there are offers you should better avoid. Have you checked whether there is a microscopy group in your area? You could get help there and maybe buy an instrument from one of the members.

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Re: Starting with identifying a decent microscope

#11 Post by Amoeba » Mon Nov 27, 2017 9:37 pm

Well the nearest to 'local' that I could find was this site:

http://microscopy-uk.org.uk/

I am currently trying to read through some of the information here. The site is a little cluttered which makes it rather challenging to navigate but it does provide some useful information. It seems to be affiliated with Brunel Microscopes in the UK who do sell used microscope equipment. Interestingly they have a Wessex trinocular (thinking useful for webcam attachment) for 195GPB. is Wessex one of those stencil brands? I'm considering it as a plan B in case I loose the Watson. The seller has come back to me to say he will answer my query tomorrow. Anything can happen in 24hrs though.

I did also come across this:

http://www.quekett.org/

A fair bit of information it seems, but you have to pay to join in order to access much of the site.

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Re: Starting with identifying a decent microscope

#12 Post by photomicro » Mon Nov 27, 2017 10:13 pm

Not sure where you are in the UK, but I have just cleared out the study of a dear friend who died earlier in the year, and left several microscopes.

Thus, the following are available;

1. Letz SM-Lux, mechanical stage, trinocular head, choice of Leitz optics, LED lighting.
2. Zeiss GFL with binocular head, mechanical stage, built in lighting, choice of Zeiss optics.
3. Olympus KHS stand, binocular head, built in lighting, olympus objectives and eyepieces.
4. Russian Biolam stand, choice of optics, round stage.

Worth asking others to comment on these, but all give good images. I can send pictures, and they can be viewed in North Yorkshire.

PM me if you have further questions.

Mike

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Re: Starting with identifying a decent microscope

#13 Post by Amoeba » Mon Nov 27, 2017 11:19 pm

photomicro wrote:Not sure where you are in the UK, but I have just cleared out the study of a dear friend who died earlier in the year, and left several microscopes.

Thus, the following are available;

1. Letz SM-Lux, mechanical stage, trinocular head, choice of Leitz optics, LED lighting.
2. Zeiss GFL with binocular head, mechanical stage, built in lighting, choice of Zeiss optics.
3. Olympus KHS stand, binocular head, built in lighting, olympus objectives and eyepieces.
4. Russian Biolam stand, choice of optics, round stage.

Worth asking others to comment on these, but all give good images. I can send pictures, and they can be viewed in North Yorkshire.

PM me if you have further questions.

Mike
That's a kind offer and I have PM'ed you.

Amoeba
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Re: Starting with identifying a decent microscope

#14 Post by Amoeba » Tue Nov 28, 2017 2:35 pm

BTW, what is the advantage of a round stage?

Also, what type of oil is used with 100x oil immersion objectives? Do such objectives also work without oil?

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Re: Starting with identifying a decent microscope

#15 Post by Micro-Bob » Tue Nov 28, 2017 3:12 pm

My recommendation was less an internet site but more a group of people who actually meet in person.
In microscopy you often need very special chemicals and materials in small amounts and for a beginner its also not easy to learn the basics just from a book.

The immersion oil is part of the optical calculation and has to have the right refractive index. Your front lens sits in it, so it should better be compatible with the lens cement. Without oil you don't get a useful picture. There are dry objectives up to n.A 0,95 with a correction collar for different cover glas thicknesses, but they are not easy to use and difficult to find on the market.

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Re: Starting with identifying a decent microscope

#16 Post by apochronaut » Tue Nov 28, 2017 4:03 pm

Amoeba wrote:BTW, what is the advantage of a round stage?

Also, what type of oil is used with 100x oil immersion objectives? Do such objectives also work without oil?
A round stage allows for more flexibility in positioning the sample but they are often used on a polarization microscope, in order to rotate the sample a precise number of degrees. Round stages, usually carry a premium and unless you are offered one at a very good price, a square stage with coaxial or even separate controls will do perfectly well, for most samples.

Any objective requiring immersion will have it's N.A. seriously reduced, and always below 1.0, when used without it's immersion medium. Additionally, it will almost always suffer from spherical aberration and render images with a foggy out of focus look to them. There are some objectives that suffer mostly from N.A. reduction and much less so from spherical aberration, when the immersion medium is altered or even when they are used dry but they are uncommon. The AO cat.# 1026 50X .85 oil immersion ∞ is one such.

An ideal oil needs to have a refractive index of around 1.52 , so special immersion oils have been chosen or synthesized on that basis but there is nothing wrong with using a clear vegetable oil in a pinch, such as sunflower . The refractive index of most vegetable oils is around 1.47, so there will be a slight reduction in resolution, noticeable but slight. It is very slight, if a 1.25 or higher N.A. condenser is oiled as well. Vegetable oil on both condenser and objective gives at least as good an image as immersion oil on the objective and the condenser in air....which is the way a lot of microscopy is done.

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Re: Starting with identifying a decent microscope

#17 Post by Amoeba » Tue Nov 28, 2017 4:44 pm

Micro-Bob wrote:My recommendation was less an internet site but more a group of people who actually meet in person.
In microscopy you often need very special chemicals and materials in small amounts and for a beginner its also not easy to learn the basics just from a book.
That's a fair point although I'm not aware of any such reasonable local group the moment. I will keep my eyes and ears open. I noticed a mentione of chemicals on microscopy-uk.org where I read about a guy named Michael Reese in his article called 'Diatoms from Santorini, Greece' saying he used 50% sulphuric acid to dissolve the chlorophyll in diatoms. He then used bicarbonate of soda to neutralise the acid. He also mentioned being treated with ouzo, but I don't think that was for the microscope....
apochronaut wrote: A round stage allows for more flexibility in positioning the sample but they are often used on a polarization microscope, in order to rotate the sample a precise number of degrees. Round stages, usually carry a premium and unless you are offered one at a very good price, a square stage with coaxial or even separate controls will do perfectly well, for most samples.
I asked because one of the microscopes offered by photomicro has a round stage. I do not believe it has a polarizer though as light is provided via a mirror. From the information given it does not seem like something I need worry about for now.
apochronaut wrote: An ideal oil needs to have a refractive index of around 1.52 , so special immersion oils have been chosen or synthesized on that basis but there is nothing wrong with using a clear vegetable oil in a pinch, such as sunflower . The refractive index of most vegetable oils is around 1.47, so there will be a slight reduction in resolution, noticeable but slight. It is very slight, if a 1.25 or higher N.A. condenser is oiled as well. Vegetable oil on both condenser and objective gives at least as good an image as immersion oil on the objective and the condenser in air....which is the way a lot of microscopy is done.
After using oil, can the objective be cleaned with IPA, or is something else recommended?

I do not yet have a full understanding of the function of the condenser, except that it serves to focus light correctly on the sample and needs to be set up correctly for the light to be evenly dispersed. I was not aware that it can also be oiled although from your comment is seems having the condenser in air is not particularly detrimental. I do however now understand that the oil has an affect on the refractive index and that slide cover thickness does matter, although I gather that slide covers have a standard thickness of 0.17mm.

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Re: Starting with identifying a decent microscope

#18 Post by apochronaut » Tue Nov 28, 2017 8:16 pm

OIl can be removed with a mild solvent. Xylene, used to be the preferred solvent but it has come under fire for it's liver toxicity. Heptane is as good and less toxic. Lately, I have been using ethanol, which works pretty well. The bulk of the oil can be removed simply by wicking it up. Cotton swaps work well but finish with something lint free. There are many different methods of getting the oil off of the front of the lens and they probably all work.


Condenser is real easy. As the objective magnification increases, it needs more light to give an adequately lit image. As the objective N.A. increases, the light needs to arrive from a broader angle in order to achieve that N.A. A higher N.A. equals higher theoretical resolution. The condenser fulfills both functions, it concentrates and focuses light and as it's N.A. increases it provides light from an increased angle. Ideally, the condenser N.A., should match the N.A. of the objective. The iris diaphragm is used to adjust the N.A.

Some condensers have an N.A. scale stamped where the lever that controls the iris diaphragm slides in the body.

In order for a condenser to achieve it's stamped 1.25 N.A. or whatever, it must be in contact with the bottom of the slide through a medium that has the same refractive index as the glass used for the slide and the condenser's top lens : certain oils meet this requirement. A condenser used dry, will have an N.A. below 1.0( usually about .90, unless it is a modified partial condenser or a special low N.A. model).

When the condenser is used with an air gap, it's N.A. while illuminating a properly immersed objective with an N.A. higher than the condensers N.A. will limit the N.A. of that objective. The prevailing wisdom is that the effective N.A. of such a system will be pretty close to the sum of this formula. Condenser N.A. X Objective N.A. ÷ 2 = effective N.A.

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Re: Starting with identifying a decent microscope

#19 Post by MicroBob » Tue Nov 28, 2017 10:47 pm

From my experience ethanol is quite critical as a cleaning medium. Try e.g wiping a red Victorinox swiss officers knife - the tissue will be red afterwards. I think I read that at least some german makers explicitly said not to use ethanol, but surgical spirit. Lighter fluid should be usually good enough. If you start to buy objectives new for real money you might just buy what the maker recommends now.
Most of the time the oil immersion objective just has to be wiped slightly with a clean tissue so it doesn't pass oil onto slides that are viewed with the dry objectives. After some time this oil would start to gum up, so this would be the right time to really clean it.

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Re: Starting with identifying a decent microscope

#20 Post by Tom Jones » Wed Nov 29, 2017 3:12 am

Amoeba,
I did also come across this:
http://www.quekett.org/
A fair bit of information it seems, but you have to pay to join in order to access much of the site.
Since you are in the UK, and new to this (and actually even if you were not) Queckett is one of the best resources available. LOTs of local meetings you can attend and learn from. Lots of very long-time amateur microscopists. Find a local meeting and go. You'll be amazed at what you can learn. And I'd probably do it before I spent more money on a microscope. It would be well worth the wait, so you don't end up spending money for something that won't do what you want. They can also probably put you in contact with someone local to help point you in the right direction if you can't attend a meeting, and actually show you what's reasonable. Hands-on beats reading of the internet any day. The UK is much better at local meetings than is the US. Full disclosure, I'm a member even though I live in the US.

There is also the Facebook Amateur Microscopy group: https://www.facebook.com/groups/Amateur.Microscopy/

As for oil... modern immersion oils do not dry out. They're not going to badly gunk up your objective. Wipe it off gently with a cotton ball or swab, to keep it off the slides when using non-oil lenses, then just add more oil the next time you use it. If it will be a long time, or you have junk in the oil from using oil on non-cover slipped slides (like grams stains, or blood smears), cleaning it isn't a bad idea. I've used 70%-90% isopropyl (rubbing) alcohol successfully for 40+ years. I use it with cotton balls or swabs to clean oil off cheap objectives, and I use the same stuff to clean $2500 PlanApos as necessary. Clean gently, and with a circular motion. Don't reuse the cotton ball or swab. Once then into the trash. Use a reversed eyepiece as a 10x magnifier to examine the objective to check your progress.

Tom

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Re: Starting with identifying a decent microscope

#21 Post by KurtM » Wed Nov 29, 2017 3:47 pm

Here's another plug for joining the Queckett Microscopical Club, or QMC for short, particularly if you're in the UK.

Tom, you mention using cotton balls or cotton swabs, is this to say just any will do? Q-Tips for swabs, say? Cotton balls from the grocery store? I was taught to use lens tissue to blot oil off, not wipe. Not saying "right" or "wrong", just what I was taught.

I second this also: Use a reversed eyepiece as a 10x magnifier to examine the objective to check your progress.
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Re: Starting with identifying a decent microscope

#22 Post by apochronaut » Wed Nov 29, 2017 3:49 pm

MicroBob wrote:From my experience ethanol is quite critical as a cleaning medium. Try e.g wiping a red Victorinox swiss officers knife - the tissue will be red afterwards. I think I read that at least some german makers explicitly said not to use ethanol, but surgical spirit. Lighter fluid should be usually good enough. If you start to buy objectives new for real money you might just buy what the maker recommends now.
Most of the time the oil immersion objective just has to be wiped slightly with a clean tissue so it doesn't pass oil onto slides that are viewed with the dry objectives. After some time this oil would start to gum up, so this would be the right time to really clean it.
The prohibition against ethanol, acetone and most other solvents for cleaning immersion oil off, is related to their potential negative affect on older Canada Balsam lens cement. This is obviously a potential issue because the cement is soluble in a number of solvents. however, if the solvent can migrate that far into the lens( the front element is almost never a cemented lens), then there is already a problem and the immersion oil has likely also migrated that far, as well. Canada Balsam also appears to be soluble in certain immersion oil formulas( cedar oil for sure). More often than not, when an older objective( usually a 40X but sometimes, sealed oil immersion objectives too) gets broken down in order to remove unintended oil seepage, if the oil has made it as far as the lower cemented doublet, the cement will have failed. Cleaning dry is best but most newbies make the mistake of not using enough dry passes and re-using already soiled tissues or swabs. This will eventually lead to scratching of the coating or glass. You need 4 or more clean passes to clean an oil immersion lens dry and it needs to be very gentle. MInor , dry cleaning can leave streaks of oil that when re-immersed in oil, soon homogenize, but if they are left too long, they will harden and affect image quality.
I usually mix a water soluble solvent, a tiny amount of dish detergent and distilled water, to make a cleaning solution and rinse with water + a couple of dry passes. Synthetic swabs are poor. Cotton is best. Heptane is best for a very quick thorough, solvent based clean up of immersion oil.

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Re: Starting with identifying a decent microscope

#23 Post by Tom Jones » Wed Nov 29, 2017 4:26 pm

Kurt,

Yes. Q-Tips and cotton balls from the grocery store or pharmacy, but gently. Pressure can drive any hardened debris into the soft optical glass of the lens and cause a scratch.

I really dislike lens tissue. People tend to just stick it on their finger and rub it flat on the objective lens, usually without even removing the lens from the microscope to look at it first. That locks any debris in place on the tissue so you just move it around under finger pressure. If you've ever looked at an objective with a bunch of scratches on the lens, that's probably how they got there. If you use it, be GENTLE, and make a little loose wad of it first, but even that tends to streak. Cotton tends to move the debris away from the glass surface.

I'm not fond of manufacturer's lens cleaning fluid, either. It all seems to leave a residue I need to remove with a little moisture. DI water with a little bit of dish detergent works fairly well, if the contaminant is water soluble, but you may need straight DI water, or moisture from your breath, to clean off any remaining soap film.

What ever you use, remove the objective first and examine with a 10x magnifier to see what it is you need to clean off, and where it is. Then monitor your progress, again with the magnifier. Odds are it will take several passes to get it nice and clean.

Tom

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Re: Starting with identifying a decent microscope

#24 Post by KurtM » Thu Nov 30, 2017 1:39 am

I suppose we should have started new threads some time back, but it's fairly hijacked now, sorry Amoeba! 8-)

Tom, I heartily distrust both lens tissue and cotton since we can never be sure what's really in them. I only use lens tissue to blot immersion oil off, and always folded to at least 4 layers for cushioning, and only enough pressure to get the job done; lots of light little dabs until the paper comes up more or less dry, maybe 5 or 6 dabs. When cleaning objective lenses I always remove them first, initially examine (does it really need cleaning, is there grit, etc.?) and then follow progress with reversed 10x eyepiece and good light, use Q-Tips, and a cleaning solution formulated by a long-established microscope repair shop here in Houston. And yes, often several passes, however many needed. I seldom clean my working oil lenses, just dab off the excess oil when done and call it good.

I don't mind running all this past you, sounds like you've been at it for a while and know what you're doing. And I have some fairly dear glass, and want to get all this just exactly right!
Cheers,
Kurt Maurer
League City, Texas
email: ngc704(at)gmail(dot)com
https://www.flickr.com/photos/67904872@ ... 912223623/

Amoeba
Posts: 60
Joined: Mon Nov 27, 2017 12:27 pm

Re: Starting with identifying a decent microscope

#25 Post by Amoeba » Thu Nov 30, 2017 1:20 pm

No problem with regards to hijacking. All the comments have stemmed from questions that I have asked and all have provided useful information.

I have used lens tissue paper from various sources for my cameras and telescope in the past but have always been a little suspicious of some papers which seemed to be rather hard. For cleaning telescope eyepiece lenses I used Baader Optical Wonder fluid. It was recommended by the astronomy community and works very well to clean off greasy smudges. I'm not sure whether it is suitable for microscope lenses though.

I now tend to use Qtips rather than lens tissue. As everyone has said, gently does it. The idea being to gently clean and not rub so as not to damage the coating.

I note with interest that oil does not need to be cleaned off after every usage as well as the tip with the reversed x10 eyepiece.

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