Some Microscope Queries

[wombat2go]

I am considering to buy a used/surplus microscope for my young sons ( 9 & 11) , and also for my own use.
I did some research. I had a microscope back in early 1960's but, out of touch, I have some queries.

1) I read that kids have difficulty with binocular eyepieces.
At what age can they use binocular?

2) I am mostly K-mount here. Any tips about binocular vs mono eyepiece for a camera mount?

3) What is an optimum magnification to view grain of C41 medium format negs?
Is the stage of an ordinary student microscope suitable for medium format negs?

4) My little student microscope was returned to me recently. It was used in a school for a while after I had it.
I think this is a generic Japanese half scale diecast microscope from 1950's
The objectives are very dirty - unusable
Is it feasible to try to clean these , and with what solvent?
The objective threads are either 12mm or 1/2 inch. I can't find any reference on internet.
Suppliers only mention the RMS thread.
Does anybody know of a supplier for these old 12mm objectives?

I will appreciate any assistance.
Regards

 

[tkamiya]

I can help you with a few.

There are two binocular types. Convergent type and non-convergent type. Convergent type has eye tube slanted slightly so that your eyes are positioned more like normal. Non convergent type has eye tubes parallel. So you look as if you are looking at distance although the image appears much closer. Even adults have trouble with the latter but is the most common type.

It's much easier to show it graphically. See here: http://en.wikipedia.org/wiki/Stereo_microscope
Second image on right shows the difference. Top is convergent, bottom is non-convergent. Top is easier, but bottom is more common.

Then.... there are stereo microscopes which usually go from 10x to 40x and compound microscope that goes from 100x to 1000x. It is waste to go any higher, although folks do sell up to 2000x. You don't get any more detail. Optical resolution is limited to around 1000x.

For your young son, I'd recommend stereo microscope. You have plenty of choices for easier convergent type. He can put a bug or something and easily see it magnified. There is no need to prepare a slide. I have one made by Labomed. (an Indian company) You can find one everywhere actually. Just search or google "Stereo Microscope".

To attach a camera, you'll need a trinocular type. These cost more. I'm not sure if you really want it.

I can keep going but I'm going to stop here as I can easily write a book..... Please ask me questions and I'll be glad to share what I know.

 

[winger]

What he said is good. Knowing your price range would help some, too. I was a chemist in a crime lab for 14 years and was one of the few who could claim much of a microscopy background. I found several decent used 'scopes on various surplus sites a few years ago. Hubby bought me a stereozoom like what we had at the lab ( <3 hubby ) - it's a decent intro for kids, too, though it's basically what some would call a dissecting 'scope. You see the surface structures; the light shines on the subject, not through it. This is pretty close - http://www.ebay.com/itm/Leica-Wild-...387?pt=LH_DefaultDomain_0&hash=item43d43854f3
For adding a camera, I know this is APUG, but at the lab we used little digi P&Ss that would fit in the opening for the ocular lens - really worked the easiest.
When I took a fiber microscopy class, I would swear WVU had just gotten a bunch of Lomo branded scopes for the undergrads. I don't know if they're still out there, but they weren't half bad for a non-lab situation.

I don't know the optimum magnification for looking at grain, but I used a scope like the one I linked to on ebay above to color some B&W 35mm slides with oils and I was not at top magnification.

 

[Mustafa Umut Sarac]

When I was 6 years old , my father bought me an monocular , no light but bottom mirror light source microscope. I was looking to pressed flies at it and it was a nightmare scene. But your childen are older than I was and the funny thing could be to see the living organisms in the water like the first microscope of the world. I dont know there are phase microscopes for cheap but sharper and more interesting the things , the more time they would invest in. I think mineralogy microscope could be very interesting also. May be geology is cheaper than medicine at the university payments also.May be you can buy roman , byzantine coins and ask them to find a way replicate them. Or giving them film negatives , platin or glass or autochrome plates.... Wow , endless.

 

[Rich Ullsmith]

Second the idea of looking at university surplus webites. Usually cheap enough you can't make a bad mistake.

 

[wombat2go]

Thanks very much to all for the advice.
I did some reading about stereo microscopes, and i found an older
Bausch & Lomb StereoZoom 4 Microscope with Plain Stand

at BMI Surplus ( I have purchased from them previously)

I think it has the convergent binocular mentioned by Tkamiya and it has adjustable spacing

It is 0.7~3 zoom and has 10X eyepieces.

Tonight , with nothing to lose on the little vintage microscope here,I washed all the lenses in distilled water.
It has improved the contamination but is still not very good.
It should be OK on 200X and 300X for viewing some moving microbes in an infusion.

Thanks,

 

[Truzi]

My parents got me a microscope for Christmas when I was a kid. Monocular, with the reflecting mirror. We went outside to catch snowflakes on slides as soon as we were done opening gifts.

Your kids should be fine with stereo microscopes, but provided they're young enough, they will enjoy just about anything you get. I would suggest one with it's own light. Of course, you have to get the kids some pre-mounted slides, brine shrimp eggs, and maybe some protozoa mix.

University surplus is a good idea; though I work at a university and frequently bid on surplus equipment, I've yet to see a microscope come up. Be patient, and you may find one.

 

[andrew.roos]

Just to throw in another option, I recently purchased a Celestron handheld digital microscope pro for my home-schooled kids to use. One of my concerns was whether my 5-year-old would be able to use a conventional stereoscopic microscope. This one allows you to display images in real time on a computer monitor, as well as capture both still images and video footage.

There are some negatives. It can be a touch tricky to focus due to the refresh rate and some backlash on the focus control. To make major changes to the working distance you need to undo a lock nut and move the microscope assembly up the post; the focus knobs on the side have a limited range of movement but are fine for focusing once the head has been set to the correct level. DOF is small at maximum magnification and of course the image is not stereoscopic. The microscope assembly, while reasonably made, is not as robust as a good optical microscope would be. And it does not have a mechanical stage, only clips.

That aside, the results are quite useable. See e.g. this image of a ruler. The vertical white lines are one millimeter (1/25 inch) apart and when I view it 1:1 on a 24" screen, the magnification is about 275x. This was taken at maximum magnification; minimum is about 18x.

To answer your question about negative grain, see this image of a small section of Delta 100 negative at maximum magnification (about 275x when viewed 1:1 on a 24" monitor). I just clipped it under the stage clips and used the built-in LED lighting illuminating it from above. The grain is clearly visible, although it's too small to analyse shape etc properly. Delta 100 is a fine-grain film. (Sorry I don't have any C41 negs to test for you).

I apologise if I have broken a taboo by mentioning a digital imaging system on APUG.

 

[wombat2go]

The "Bausch & Lomb StereoZoom 4 Microscope with Plain Stand" arrived yesterday.

It is in good shape optically and mechanically with a few paint burnishes and scratches from use
I think it is ideal for the needs here, and I thank the above members for suggesting this type, because I would not have known about it otherwise.


Last night the boys had a session examining some food items.
So far they are just using one eyepiece

It is a good way to teach them how to manually focus, because in low zoom it has a forgiving depth of field.

I suppose by the time they get to college, they will all be using a monitor like Andrew's kids are and there will be no manual focus.

It does concern me that technology is tending to add layers of software between humans and reality, and the younger ones are so dependent on computer apps to do anything.

*****
Here is a long shot query about the microscope adaptor.

This microscope has an adaptor underneath for 2X adaptor and illumination adaptors etc.
I can't find the thread standard, except by measurement that it is either "ISO 38mm" or 1.5 inch female thread.

Does anybody know what the thread would be on this old Bausch & Lomb , and what the thread angle and pitch is?

The reason is, the Bausch & Lomb 2X lens accessory will cost as much as the whole microscope did.
I have a Pentax Dental macro here with a kit of magnetic close up lenses with the 49mm by 0.75 mm lens filter thread.
By hand testing, it appears these close up lenses will work under the microscope too, and the spacing to the stereo lenses does not seem critical.
.
I just need to make an adaptor on the lathe for the microscope thread to the 49mm filter thread.
If I can't find the thread standard I will make some trial threads which takes a bit of time.

So I would appreciate any info on that Bausch & Lomb adaptor thread. /thanks

 

[Rick A]

Check this place out.

http://www.scientificsonline.com/shop/microscopes

 

[wombat2go]

Thanks Rick
The major microscope and telescope suppliers do put good info up.
I have not found the Bausch & Lomb thread type yet.

with a loupe looking in on an angle I can't measure the thread pitch at all accurately, I can narrow the possibilities a bit.
It might be one of :

1) ISO 38mm by 0.75mm which is commonly used for camera ports on microscopes.
2) 1.5 inch by RMS ( Royal Microscopy Society) thread which was 36 turns per inch of British Whitworth thread form (and is still one standard for objectives.)
3) 1.5 inch by 32 turns per inch of Unified 60 degree thread.

 

[Dan Fromm]

Meandering marsupial, if you're not aware of this http://www.microscopy-uk.org.uk/ already you might find it interesting.

 

[wombat2go]

Thanks, Dan
Your link has a few hits on the StereoZoom4 - was released in '59 and came to prominence in industry in '80's
Do you happen to know about when the ISO 38mm camera mount originated?

I think I will make a 38 by 0.75 mm thread and see if it screws in to the microscope.

Of course I can't get the annular magnet for the Pentax Dental close ups, but I think I can inlay some of the small neo magnets available on Amazon into the annulus of the adaptor I make.

 

[Dan Beaman]

Hi Wombat,
I'm resurrecting a thread of yours. I have an old B&L StereoZoom 4 as well, and am looking to make adapters just like you were. I cannot figure out what the thread pitch is on the mount. 32 tpi, 0.75 mm pitch, and 36 tpi are all so close it is hard to tell based on the thread gage and the three threads available on the mount. It is definitely 38 mm or 1.5", but like you stated earlier, there are several variations to that. I figured I would resurrect this to see if you got the 38 x 0.75 to thread on correctly, or if you ended up with a 36 or 32 tpi instead? I was about to turn a 32 to see if it would work, but figured I would search the web first. Appreciate any help you could provide.
Thanks,
Dan (not the same as the earlier poster in the thread)

 

[choiliefan]

This is interesting because I have an AO StereoStar Zoom microscope but never realized filters could be added below the objectives.
In my case this AO scope has an accessory thread of approx 46.75mm so I'm wondering if a 47mm close-up filter would thread in?
Unfortunately I don't have any 47mm filters to test.