Kid's/student's objective standard?

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jjtr1
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Kid's/student's objective standard?

#1 Post by jjtr1 » Fri May 20, 2022 5:31 pm

Hi,

the objectives on my student's microscope (not a toy, but very short - just 25 cm) are not RMS nor DIN - the thread is 15 mm dia. and parfocal distance is 32 mm. (Tube length is hard to measure because of the 45 deg. prism.)

Would someone happen to know whether this was some antique objective standard or is it just something random chosen for kids scopes by the chinese?

Scope is similar to this:
https://zoom-n-joy.cz/product/mikroskop ... raloci-zub

Thanks!

PeteM
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Location: N. California

Re: Kid's/student's objective standard?

#2 Post by PeteM » Fri May 20, 2022 8:56 pm

Some of these small/cheap objectives would interchange since these low end scopes were re-branded by many for kids' starter scopes.

If the question beyond the question is something like "where can I buy more objectives to fit?" -- I'd suggest spending the money on a still-cheap used scope with RMS objectives and a bit higher quality. IMO, these scopes really aren't worth upgrading, given that higher quality used microscopes can often be found well under $100 and sometimes closer to $25 -- about the price of a replacement objective.

Greg Howald
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Re: Kid's/student's objective standard?

#3 Post by Greg Howald » Sat May 21, 2022 1:45 am

Those objectives come with small student scopes such as IQ Crew. Amscope offers such scopes, even in an inverted version. The inverted version even has extended focal point of 170 instead of 160. They are made in 4, 10,20, and 40x. I have not seen 100x. If you need specs or more objectives, I would try to contact IQCrew. I have not found the objectives offered seperately, but they might give you info or deal with you. These objectives work but are generally considered substandard. Good luck.
Greg

jjtr1
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Re: Kid's/student's objective standard?

#4 Post by jjtr1 » Sat May 21, 2022 8:08 am

Greg, thank you for the info! The 4x and 10x are usable (within say 12 mm field), but the 40x is junk (even with the illuminator (also junk) fixed to fill the 40x's aperture). 40x is probably too demanding for the substandard manufacturing, but 20x could be ok.

PeteM, I also have a Nikon Alphaphot-2, but the student's scope portability (it weighs less than a tenth of the Nikon) is very nice. You can hold it in one hand. Also it invites experimentation, since it's cheap and junky. I'd like to try replacing the wedge prism in the mono head with a roof prism from junk straight binoculars to get erect images. On the other hand, I wouldn't dare to touch the Nikon's optics!

GerryR
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Re: Kid's/student's objective standard?

#5 Post by GerryR » Mon May 23, 2022 6:13 pm

I don't know if these are of any interest to you. I ran across them on ebay while looking for a 100x oil objective. They are 15mm mount.

https://www.ebay.com/itm/264766327019?h ... SwURNe6WwY

apochronaut
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Re: Kid's/student's objective standard?

#6 Post by apochronaut » Mon May 23, 2022 11:59 pm

There was a sort of standard developed by the manufacturers of toy/hobby microscopes from the 50's onward in Japan, sold widely through dept. stores. Objective thread was normally hitched to the size of the body of the scope and that was hitched to it's magnification. 300X, 450X, 600X, 750X, 900X, 1200X were the normal increments in dize with 15mm objective threads being used on the smaller bodied instruments , 17mm for the middle range and 19mm for the 1200X, which also had fine focus.
The chip lens objectives themselves were built into barrels that had an 11mm thread, which in turn were threaded into the required adapter . Since the microscope bodies ranged from very small to small, the tube length may have been keyed to the objective thread diameter. I seem to remember measuring a couple : one that had 17mm and another with 19mm threads and got 125mm and 135mm tubes but my memory might be off. It was a while ago.
In the late 60's, companies like Edmund started to sell microscopes and parts with sub R.M.S. objective threads that had a better achromat construction with coated lenses and decent N.A.s The performance of those objectives was quite good and despite the superficial resemblence of them to those cheaper toy microscopes of the 50's and 60's , they were more like a small hobby scope than a toy.
Tasco sold a very diminutive cast iron bodied one in a nice hardwood cabinet that had only 5X, 10X and 30X objectives and a W.F. 10X eyepiece. Nice heavy cast iron horseshoe rsther than cast aluminum( although the real old dept. store scopes had cast iron too). The objectives were 19mm thread coated achromats and it imaged like a real microscope. The only ònes I have seen were grey.
. The 19mm objectives ifrom the toy/hobby microscpe transferred to that little Tasco were far inferior with lots of lateral ca despite being viewed through the Tasco 10X coated W.F. eyepiece.
Eyepiece diameters in those scopes were likewise in 2mm increments. 15mm, 17mm, 19mm and 21mm.

jjtr1
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Re: Kid's/student's objective standard?

#7 Post by jjtr1 » Wed May 25, 2022 11:41 am

GerryR wrote:
Mon May 23, 2022 6:13 pm
I don't know if these are of any interest to you. I ran across them on ebay while looking for a 100x oil objective. They are 15mm mount.
Those are exactly my little scope's objectives :) Ufortunately, no 20x is on sale.

But I have at least found this old 15 mm set with engraving instead if printing, showing that 15 mm objectives have been around for some time.
https://www.ebay.com/itm/284639708169?h ... Sw8ZBh~atW

jjtr1
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Re: Kid's/student's objective standard?

#8 Post by jjtr1 » Wed May 25, 2022 12:00 pm

apochronaut wrote:
Mon May 23, 2022 11:59 pm
There was a sort of standard developed by the manufacturers of toy/hobby microscopes from the 50's onward in Japan, sold widely through dept. stores. Objective thread was normally hitched to the size of the body of the scope and that was hitched to it's magnification. 300X, 450X, 600X, 750X, 900X, 1200X were the normal increments in dize with 15mm objective threads being used on the smaller bodied instruments , 17mm for the middle range and 19mm for the 1200X, which also had fine focus.
The chip lens objectives themselves were built into barrels that had an 11mm thread, which in turn were threaded into the required adapter . Since the microscope bodies ranged from very small to small, the tube length may have been keyed to the objective thread diameter. I seem to remember measuring a couple : one that had 17mm and another with 19mm threads and got 125mm and 135mm tubes but my memory might be off. It was a while ago.
In the late 60's, companies like Edmund started to sell microscopes and parts with sub R.M.S. objective threads that had a better achromat construction with coated lenses and decent N.A.s The performance of those objectives was quite good and despite the superficial resemblence of them to those cheaper toy microscopes of the 50's and 60's , they were more like a small hobby scope than a toy.
Tasco sold a very diminutive cast iron bodied one in a nice hardwood cabinet that had only 5X, 10X and 30X objectives and a W.F. 10X eyepiece. Nice heavy cast iron horseshoe rsther than cast aluminum( although the real old dept. store scopes had cast iron too). The objectives were 19mm thread coated achromats and it imaged like a real microscope. The only ònes I have seen were grey.
. The 19mm objectives ifrom the toy/hobby microscpe transferred to that little Tasco were far inferior with lots of lateral ca despite being viewed through the Tasco 10X coated W.F. eyepiece.
Eyepiece diameters in those scopes were likewise in 2mm increments. 15mm, 17mm, 19mm and 21mm.
Apochronaut, this is exactly the answer I was hoping for. Thank you for sharing your extensive knowledge!

What is a "chip lens"? A glass drop lens?

With regard to W.F. eyepieces, my little scope made about 5 to 10 years ago has one too, and it's a regular narrowfield Ramsden. I wonder why the Chinese use nonsense labeling on eyepieces when their objective labeling is ok.

apochronaut
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Re: Kid's/student's objective standard?

#9 Post by apochronaut » Wed May 25, 2022 2:16 pm

Just a little edit on those measurements. My memory was mixing up eyepiece and objective measures. I have a few of those older toy/hobby microscopes here and I did some measuring. The objective thread appears to be either 10 ,10.5 or 11mm. Some of the really small instruments may have been less. 10mm seems to have been a norm for the average size small microscope, threaded into an adapter that was either 14,15 or 16mm.

I have a couple of loose objective adapters here : one 10mm x 16mm and another 11mm x 15mm. You can have the 15mm one if you can use it. It has a built in diaphragm or baffle at the 15mm end. That way, if you came across an objective in a different adapter you could use that one. A 10 or 10.5 mm objective could probably be fitted into the 11mm adapter with some shimming. Teflon tape or electrical tape.

The objectives you linked to, based on the colour code rings and the construction of the front lens are likely later 70's or early 80's production. One of the major manufacturers of sub standard objectives, Carton Optical moved their production to Thailand when it became too expensive to manufacture in Japan and other company's production moved to China, where they already made sub standard size microscopes. India too. Eventually the practice of making standardized small objectives out of chromed brass was abandoned in favour of miniature objectives with a shroud made of either aluminum or plastic. Sometimes the optics are plastic too.

Chip Lenses.
The chromed brass common objectives up until the 70's at a maximum had a standard bore to accomodate standardized chip lenses. These were standard diameter bispheric lenses of several magnifications that were dropped into the bore on spacers. They were stacked to achieve the required magnification. A 10X objective would be a 5X and a 2X for instance. There wasn't any attempt to achromatize although with the higher magnification objectives, 45X and 60X, the front lens was a sealed in plano convex followed by spaced chip lenses. There may have been a crown glass, flint glass air spaced achromat in there because they usually perform better than one would expect. Similar objectives were made in the 19th century : stacked objectives. These were objectives that had usually 3 elements, sealed in their own brass cell and each threaded on to the one above. Magnification was multiplied that way. The initial magnification with a 10X eyepiece would be 50X or so , then 100X and then 200X using a single objective.

Later objectives built for pure hobby or educational microscopes had more sophisticated optics, with sealed plano/convex front lenses, and a larger bore but as a way of economising they made smaller barrels and threads. A 30X on the Tasco Student microscope above is 10mm with a 15mm adapter, in aluminum.
Those objectives in the last link look like they separate out as well. My guess would be Chinese or Indian. Unfortunately, 20X are not that common because they almost always had a 10X and more often than not a 20X eyepiece to pad out the magnification.
Last edited by apochronaut on Tue Feb 14, 2023 10:09 am, edited 1 time in total.

apochronaut
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Re: Kid's/student's objective standard?

#10 Post by apochronaut » Thu May 26, 2022 9:45 am

Here are 2 sub sized objectives plus the 15mm adapter referred to above along with one of the 7 wonders of the microscope world.

In the foreground left to right are a 60X objective with a 16mm thread and a 30X objective with a 14mm thread. Each objective barrel has it's own thread : one 11mm and the other 10mm and are in turn threaded into their respective adapters or collars to fit the microscope nosepiece.
On the right is a separate adapter with a built in diaphragm. 11mm i.d. and 15mm o.d. Most of these objectives in the day were built like that.

The 7 wonders of the world microscope is a Lumex 600X with 4 fixed in objectives and a fixed in 10X eyepiece : so prying fingers couldn't modify the design. As you can see it is 8" tall and the only non metal parts are the bakelite eyelens mount and the illuminator switch knob.The focusing is rack and pinion with machined aluminum knobs. Cast, with grey crackle enamel. The whole thing weighs a whopping 14 oz., including electrics. Even the plano mirror case is steel.

It came in a fitted, dovetailed, solid, blonde varnished, hardwood case. Not plywood. Looks like some sort of Ash to me. Remarkable, really.

The second picture profiles 3 - 60X objectives. the one on the left is 45mm parfocal R.M.S.
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jjtr1
Posts: 33
Joined: Sat May 07, 2022 8:51 am

Re: Kid's/student's objective standard?

#11 Post by jjtr1 » Fri May 27, 2022 2:15 pm

That giant 63x objective is really RMS/DIN? :) It dwarfs the entire microscope... The bulkiness of today's objective bodies hides the diminutivness of the lenses inside...

Altogether, I feel awe and respect. The hardwood case indicates how laborious and expensive it was to do even a toy/hobby microscope in those days (a case like that would double or triple the price of todays toy scope since they're so cheap).

Also how incredible today's manufacturing is, for putting out precision parts at light speed and almost zero cost. Getting a new DIN 10x achromatic objective with coatings for $20 is normal, yet it's ridiculous. Part of it is of course the currency exchange rate, but still.

History of technology usually only shows the products, and not the "machines that make the machines (products)", which is where the progress really lies.

Thank you for sharing!

DickensRyan
Posts: 1
Joined: Thu Nov 10, 2022 2:08 pm

Re: Kid's/student's objective standard?

#12 Post by DickensRyan » Fri Nov 11, 2022 12:17 pm

apochronaut wrote:
Mon May 23, 2022 11:59 pm
There was a sort of standard developed by the manufacturers of toy/hobby microscopes from the 50's onward in Japan, sold widely through dept. stores. Objective thread was normally hitched to the size of the body of the scope and that was hitched to it's magnification. 300X, 450X, 600X, 750X, 900X, 1200X were the normal increments in dize with 15mm objective threads being used on the smaller bodied instruments , 17mm for the middle range and 19mm for the 1200X, which also had fine focus.
The chip lens objectives themselves were built into barrels that had an 11mm thread, which in turn were threaded into the required adapter . Since the microscope bodies ranged from very small to small, the tube length may have been keyed to the objective thread diameter. I seem to remember measuring a couple : one that had 17mm and another with 19mm threads and got 125mm and 135mm tubes but my memory might be off. It was a while ago.
In the late 60's, companies like Besides this I often resort to this source https://phdessay.com/essay-type/exploratory/ to do exploratory essays, it helps me a lot in college and besides this I create my own library where I will collect all my study materials, namely the fact that I don't spend my personal time for this I enjoy it a lot, I manage to do more and generally I feel like a real student because I have time to go out with friends and have fun. 50's and 60's , they were more like a small hobby scope than a toy.
Tasco sold a very diminutive cast iron bodied one in a nice hardwood cabinet that had only 5X, 10X and 30X objectives and a W.F. 10X eyepiece. Nice heavy cast iron horseshoe rsther than cast aluminum( although the real old dept. store scopes had cast iron too). The objectives were 19mm thread coated achromats and it imaged like a real microscope. The only ònes I have seen were grey.
. The 19mm objectives ifrom the toy/hobby microscpe transferred to that little Tasco were far inferior with lots of lateral ca despite being viewed through the Tasco 10X coated W.F. eyepiece.
Eyepiece diameters in those scopes were likewise in 2mm increments. 15mm, 17mm, 19mm and 21mm.
Looks like I learned more from this one than three years in college, lol.

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