How clear should eyepieces be?

[Daniel10868]

Hi everyone and thank you for all that I have already learned from this forum...first post.

I have an Olympus BH2 BHS that was purchased used and is my first experience with a decent compound microscope. Upon receiving it and looking at a few prepared slides I noticed it could use some cleaning, so I went about cleaning all the glass as carefully and gently, yet thoroughly, as I could. It is probably unfortunate that I also cleaned the inside of the eyepieces. Certainly I was able to improve things, but there are still noticeable imperfections, which are identifiable as coming from either eyepiece by rotating them and observing the spots move with the eyepiece. No amount of additional cleaning gets rid of them all, it just creates different spots.

My question is, how perfect should I expect this to be? Depending on magnification they may be out of focus to the point of not being observable, or they may be somewhat distracting but not really preventing observation of the slides. I have done some photography using the trinocular head and of course they are not in that path, so not an issue there. So, should I expect the view to ever be 100% clean, or do all objectives, after a bit of use and cleaning, have some visible spots.

Similarly, when using my higher magnification objectives (40x, 100x) it seems I have so many floaters in my eyes that come into focus (clearly moving with my eye and blinking) that objective cleanliness is no longer a first order issue...it's really only at medium magnifications (10x objective) that I am wondering if I should be expecting cleaner views.

[apochronaut]

In theory, the view should be really free of dirt and debris. Sometimes there will be a little on the upper surface of the eyelens but once you get the other lens surfaces clean they should stay that way. The upper eyelens surface may have to be cleaned or blown free of a bit of dust every now and then.
With some eyepieces you can rotate the eyelens section against the field lens section in order to determine where observable dirt is located and in general , debris that is more in focus is on a surface close to the field stop.
Eyepieces with more than 3 elements in 2 groups can sometimes be tricky to track down dust on the surfaces.

[GerryR]

Hi everyone and thank you for all that I have already learned from this forum...first post.
.......

Similarly, when using my higher magnification objectives (40x, 100x) it seems I have so many floaters in my eyes that come into focus (clearly moving with my eye and blinking) that objective cleanliness is no longer a first order issue...it's really only at medium magnifications (10x objective) that I am wondering if I should be expecting cleaner views.

Welcome.
I have a similar problem with floaters and have not been able to find a solution. I also have a corneal scar on my right eye, which shows up when looking through the ocular. I once sent a Swift scope in for cleaning because I couldn't rid the view of this weird-shaped debris after multiple cleanings, only to find out later that it was this scar that I was seeing. If there is a solution to such problems, outside of using a microscope camera and monitor, which I do use with my stereo 'scope, I would like to know, as well.

[Greg Howald]

Sorry. I have macular degeneration in the right eye. The camera is the only way out.
Greg

[apochronaut]

Floaters are mostly transparent and will increase with age but I distinctly remember being annoyed by them even at 12 , when I started doing microscopy in earnest. Over time, they have increased in number but they bother me less. I now also have some retinal scarring and a few of those dark blocks in the field of view are worse than 50 floaters.

Really bad floaters and scars can often be moved out of view by moving your eyes around and back and fotth across the x and y axes, giving you temporary reprieve from the worst offenders.
Floaters , seem to be bothersome more to those who are inexperienced microscopists than experienced ones. I certainly wss bothered way more by the few I had 58 years ago than the zillions I have now. You get used to them and similar to learning to be able to use a monocular microscope without squinting, you can train your brain to ignore them. To look through them, so to speak.

Mac D is a whole other thing. My wife finds a good monocular microscope to be the answer there. A binocular not so usefull but she only looks through a microscope every now and then.

[blekenbleu]

.......
Similarly, when using my higher magnification objectives (40x, 100x)
it seems I have so many floaters in my eyes that come into focus (clearly moving with my eye and blinking)
that objective cleanliness is no longer a first order issue...it's really only at medium magnifications (10x objective)
that I am wondering if I should be expecting cleaner views.

I have a similar problem with floaters and have not been able to find a solution.
I also have a corneal scar on my right eye, which shows up when looking through the ocular.
I once sent a Swift scope in for cleaning because I couldn't rid the view of this weird-shaped debris after multiple cleanings,
only to find out later that it was this scar that I was seeing.
If there is a solution to such problems, outside of using a microscope camera and monitor,
which I do use with my stereo 'scope, I would like to know, as well.

By dumb luck, all my AO infinity and Nikon finite CF microscopes have no appreciable corrections by eyepieces
which are usefully interchangeable and also replaceable by Chinese wide field, high eyepoint oculars.
Despite few significant aberration differences, Nikon's CFWN 10x/20 eyepieces provoke more distracting
floaters in my views than do AO180, AO 146 or Chinese high eyepoint WF10X/22 or WF10X-18mm in the same microscope.
Floaters can still be noticed with any combination,
but high eyepoint WF10X/22 oculars with Optiphot 210mm M Plan objectives are my preferred combination,
with floaters most easily ignored, as with brighter and higher contrast views.
If you have reason to believe that your scope's objectives do not much depend on oculars for corrections,
consider risking about US$35 on generic high eyepoint, wide field eyepieces for improved viewing comfort.
Still, best views for me are indeed by HDMI TV to Canon digital cameras in Live View mode on trinocular photo ports.

Another trick: arranging microscope heights to minimize tipping eyes down.
For example, I have one pair of scopes with oculars at about 149cm for comfortable viewing while standing,
with final heights tweaked by otherwise rarely used big old textbooks.

[PeteM]

For those with serious problems with floaters, viewing on a large high definition screen is one alternative.

Another might be a set of "Isis" eyepieces made by Vision Engineering. These have spinning lenticular disks inside that sort of smear the image of floaters. They might help. I came across a set, added the needed DC supply, and tried it. While I have floaters, I'm not much bothered by them. However, the fellow I passed this along to, more bothered by floaters, said it was a significant help. No longer made, but sometimes found cheap enough to try used. They look like this:

https://midwestmicroscopeboneyard.com/p ... epiece-set

As for cleaning eyepieces, used ones sometimes come needing a thorough cleaning - sometimes dismantling. With kids using a scope, finger prints appear on the top lens all the time. One reason why ex-school microscopes seem to have the coatings worn off eyepieces?

That said, eyepieces kept covered in a relatively dust free room shouldn't need frequent cleaning. IMO only a photo relay lens needs to be kept more or less spotless whenever it's used - and even then a photo editor can help.

[Scarodactyl]

No amount of additional cleaning gets rid of them all, it just creates different spots.

How are you cleaning them? It is easy to end up just pushing duat or oil around on the surface.

[apochronaut]

.......
Similarly, when using my higher magnification objectives (40x, 100x)
it seems I have so many floaters in my eyes that come into focus (clearly moving with my eye and blinking)
that objective cleanliness is no longer a first order issue...it's really only at medium magnifications (10x objective)
that I am wondering if I should be expecting cleaner views.

I have a similar problem with floaters and have not been able to find a solution.
I also have a corneal scar on my right eye, which shows up when looking through the ocular.
I once sent a Swift scope in for cleaning because I couldn't rid the view of this weird-shaped debris after multiple cleanings,
only to find out later that it was this scar that I was seeing.
If there is a solution to such problems, outside of using a microscope camera and monitor,
which I do use with my stereo 'scope, I would like to know, as well.

By dumb luck, all my AO infinity and Nikon finite CF microscopes have no appreciable corrections by eyepieces
which are usefully interchangeable and also replaceable by Chinese wide field, high eyepoint oculars.

That's a very good observation. The first iteration of AO infinity objectives were as ca corrected as was possible at the time but that was mid.-60's. The early Nikon CF effort about 10 years later required a very similar eyepiece correction, so Nikon CF eyepieces are virtually identical to the early AO eyepieces used for the 34mm infinity system in terms of their corrections. It's surprising because design wise the AO and Nikon eyepieces are quite dissimilar but you can for instance install an AO # 176 eyepiece with it's plano eyelens in one tube and a Nikon CF eyepiece with it's convex eyelens in the other tube and use them as a pair. The AO is 19mm f.o.v. and the Nikon 18mm but your eyes default to the narrower field and they are oddly, parfocal. The extra 2mm f.o.v. that a #180 adds is too much and despite similar peripheral corrections , an AO 180 and Nikon CFWE 10X/18 won't work together and cause eyestrain, despite parfocality.
I haven't notced any difference regarding floater interference. Floater interference is also affected by the type of sample. Stained samples or high contrast samples are not as obscured by them as neutral coloured samples.

[imkap]

When very dirty I disassemble and wash lens with soap and tap water gently with my fingers. Later rinse with distilled water and wipe with lens cloth. Worked pretty good and made no scratches or coating damage this way... Just draw how to assemble the lens later, as it tends to evaporate through the ears occasionally.

[apochronaut]

That works. I am guessing you mean dish detergent? It usually rinses very thorougly whereas actual soap, can leave a film.

[imkap]

That works. I am guessing you mean dish detergent? It usually rinses very thorougly whereas actual soap, can leave a film.

I actually used regular soap but a very light amount, just made a few bubbles on my fingers
Thanks for the tip, now I know

[Daniel10868]

No amount of additional cleaning gets rid of them all, it just creates different spots.

How are you cleaning them? It is easy to end up just pushing duat or oil around on the surface.

I blow the dust off, if any, with a bulb+brush from a camera cleaning kit, and if dust is still present I use a bit of lens cleaning solution, or I use 90% isopropyl. I use a swab gently spinning and circling the lens and wipe with kimwipes, or sometimes use kimwipes with a touch of alcohol. They look perfectly clean if you just look at them outside the scope, but when observing there are little blotches (out of focus) that rotate with the eyepiece. I use a similar technique for cleaning camera and telescope lenses, although the rule there is generally to avoid cleaning unless really necessary as you can create scratches and a little bit of dust doesn't usually affect a camera or telescope view significantly...but for a microscope my experience seems to be any imperfection on the eyepiece can create a smudge or fine hair in the view. Also microscope slides seem to have a lot of flaws in the glass that create most times even more (out of focus) smudges in the view - cleaning the slide often helps if there is dirt or dust but a lot of it is in the glass it seems.

I'd be afraid to put an eyepiece under water for fear of making it worse.

[apochronaut]

The recommendation to use water and detergent is based on removing the lenses and cleaning each separately. That method works quite well but the lens must be dried manually. Tap water will leave mineral deposits. I use a combination of water and 5% distilled vinegar as a rinse agent.

You are most likely leaving fibres behind from the kimwipes etc. Their may be some persistent specs too. Dust particles can become adherent after periods of humidity or condensation. It's more than just static. Airborne vapours, even car exhaust or cooking fumes become like a glue.

I have cleaned a lot of old glass and it takes a while sometimes. A lot of the particles are not visible to the naked eye.
With persistant specs, I usually use a stereo microscope and pick off each particle separately with a very fine artists brush. As fine as you can find.. 000 at least. The brush is kept immaculately clean. You can use your other eyepiece inverted as a strong magnifier.Try different lighting techniques and angles. Incident, transmitted, oblique. Some particles will only show up under certain lighting. Old surfaces can be covered with bits, even excrement of tiny insects. That is persistant. There is a saying. Sticks like shit on a blanket. ....soon to be replaced by sticks like Donald Trump.

Swabs should be used for one pass only. Wiping and then finishing off by exiting the surface radially. Then brush that exit path with the artists brush, because when you pick up a swab, it leaves behind a certain amount of debris thst it has been pushing like a broom. I usually finish by giving it a twist and sliding it off the lens edge, which minimizes the amount of residual debris. By rotating the swab while moving it, you gather up most of it but do not rotate 360°. Allways move from the inside out. Keep your brush rinsed off with I.P.A. and distilled water and stored in a pencap.