Chinese microscopes

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Roldorf
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Re: Chinese microscopes

#31 Post by Roldorf » Fri May 24, 2019 1:07 pm

Bresser Plan objectives all 160.

Plan 4x .1 69,00€ £59.00
Plan 10x .25 108,00€ £92.00
Plan 20x .4 165,01€ £140.00
Plan 40x .65 175,00€
Plan 60x .85 195,01€
Plan 100x 1.25 oil 199,00€ £169.00

If you decide to go for plan objectives you would have to contact Bresser to get them fitted before shipment, or pay the extra and store the original lenses shipped with the scope.

Prices for the 40x and 60x are not listed on the UK website.
Based on the 20x which is listed as 29,00€ the planachromat's are just over 5.5 times more expensive.

So to round up a set of planachromat (4x 10x 40x 100x) lenses would cost an extra 434€ (£361@1.2 exchange rate) on the list price of the scope if they supplied the scope with the plan lenses. Note this is an estimate and things might be different if you talk to them.

In my opinion this is not worth the extra as you can buy the TRM 301 which is supplied with planachromat lenses for £764.00 and is a much better scope anyway.
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Hobbyst46
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Re: Chinese microscopes

#32 Post by Hobbyst46 » Fri May 24, 2019 2:40 pm

Interesting to note, especially in view of (our) long-term (continuing and counting) debate about LEDs vs halogen (I would compare it to Edison vs Tesla... :)), that the (relatively) expensive Bresser Science TRM301 boasts Kohler halogen light, does not even mention LED...

Citing from the description:
"...The Köhler illumination is standard for scientific research and microphotography. One gets it using the fixed field diaphragm and the height- and center-adjustable Abbe condenser..."
I would inquire what a "fixed" diaphragm means in this context.

It has an optional dedicated dark field condenser as well, I would inquire if the 20W halogen is adequate for that.
Last edited by Hobbyst46 on Fri May 24, 2019 2:53 pm, edited 1 time in total.
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Re: Chinese microscopes

#33 Post by billbillt » Fri May 24, 2019 2:52 pm

Citing from the description:
"...The Köhler illumination is standard for scientific research and microphotography. One gets it using the fixed field diaphragm and the height- and center-adjustable Abbe condenser..." I would inquire what a "fixed" diaphragm means in this context.

NOTE IT SAYS "STANDARD".. NOT "IDEAL".. KOHLER IS NOT IMPERATIVE FOR GOOD MICROSCOPY...

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Re: Chinese microscopes

#34 Post by Dave S » Fri May 24, 2019 3:24 pm

You make a valid point apochronaut, re achromatic lenses, and chromatic aberration (CA).

When I started out in astro-imaging I started out with a doublet achromatic refractor (two different dispersion acro lenses cemented together,) which while better at limiting CA than a single element (basic) acro lens, still suffered from CA in the form of violet fringing around stars. A basic achromatic lens, endeavours to bring two of the primary colours (usually red and blue) to the same focal plane, but the green still remains out of plane. Albeit, I'm sure you now this.

I soon moved up to triplet objective refracting telescopes, which gave me CA free images. Not a problem with reflecting telescopes of course which use a mirror, and an eyepiece.

What I don't know, and perhaps you, or someone here can enlighten me, is the situation with microscope objective lenses. Are the achromats just basic single glass element construction, or are they doublets. Moving up to plan objectives, are these of triplet element construction. ??

Rolfdorf, I am located in the UK, England to be more precise. I have now updated my profile accordingly.
Last edited by Dave S on Fri May 24, 2019 6:22 pm, edited 1 time in total.
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Re: Chinese microscopes

#35 Post by Dave S » Fri May 24, 2019 3:38 pm

Here is another question :)

Given that most 4 objective microscopes come with 4x, 10x, 40x, and 100x (oil immersion) objectives fitted, is it better to swap the 100x (oil) for a 60x objective.

From what I read, unless you are interested in bacteria, the 100x would be rarely used, and that for most subjects, up to 400x magnification is adequate. Would you agree?
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Re: Chinese microscopes

#36 Post by Hobbyst46 » Fri May 24, 2019 3:41 pm

Dave S wrote:...What I don't know, and perhaps you, or someone here can enlighten me, is the situation with microscope objective lenses. Are the achromats just basic single glass element construction, or are they doublets. Moving up to plan objectives, are these of triplet element construction. ??.
Here is a very good description:
https://www.olympus-lifescience.com/en/ ... bjectives/
Nikon and Zeiss sites also contain similar explanations.
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Re: Chinese microscopes

#37 Post by Dave S » Fri May 24, 2019 4:01 pm

apochronaut wrote:Since you have been involved with telescopes, I thought I would pass this along but you are already probably aware of this critical difference between microscopes and telescopes. It is one thing that many telescope users miss, when they switch over to microscopes and it can cause a bit of confusion because they are used to changing eyepieces to change the instrument's performance. You can't just do that without some careful thought and precautions on a microscope. I write this for any novice moving over from the telescope to the microscope, because I'm sure there are or are going to be some reading this thread.

To compare the two instruments directly as instruments to view something, each with an objective lens and an eyelens, the mode of use for each is somewhat reversed.

A microscope is actually several individual instruments attached to the same frame, depending on however many objectives it has. You could have an achromat, a fluorite and an apochromat, all in one stand, each coordinated to work with the same eyepiece but more often the degree of corrections of the objectives are similar and it is only the focal length or magnification that is different. The average microscope is basically 3 different size refractors all on one frame. Modifications of magnification and of corrective capacity are made by changing the objectives usually, and occasionally eyepieces too, as long as they are specifically coordinated to the objective being used or are a close acceptable match. In certain situations there are even reflecting objectives, so one can have a reflecting microscope as well. It is an array of different objectives on one stand that provides the user of a microscope, with a broader magnifying capability in general. Light gathering capacity and therefore resolving power is determined by the acceptance angle of an objective lens, plus the corrective capacity built into the coordinated optical combination.

With a telescope, the situation is generally reversed. You have to have several individual instruments and therefore objectives in their own frame, in order to equate to a microscope with a rotating nosepiece. It is an array of different eyepieces that provides the user of a telescope with a broader magnifying capacity, while using a single objective. Light gathering capacity and therefore resolving power is determined by the diameter of the objective lens, plus the corrective capacity built into the coordinated optical combination.
An excellent comparative explanation. :)

With telescopes the less well informed are attracted by the telescope in the high st shop, or mail order catalogue that says "200x magnification", which for astronomy is about a much use as a "Chocolate Fireguard".

In astronomy, we are about light gathering power, and resolution, magnification is secondary. Unlike with a microscope, we can't turn up the illumination

As you so aptly describe, a microscope can be several different optically spec'd instruments in one, depending upon how it is populated with optics.

With a telescope, we can only change the eye piece.

What does leave me somewhat amused, is you will find microscopes aimed at the hobbyist, some costing several hundred pounds, claiming magnification up to 2500x. Forgive me if I am wrong but this seems to be another "chocolate fireguard" scenario.
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MicroBob
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Re: Chinese microscopes

#38 Post by MicroBob » Fri May 24, 2019 4:05 pm

Dave S wrote:What I don't know, and perhaps you, or someone here can enlighten me, is the situation with microscope objective lenses. Are the achromats just basic single glass element construction, or are they doublets. Moving up to plan objectives, are these of triplet element construction. ??
Hi Dave,
an achromatic closeup lens for a camera is a doublet. For microscope objectives usually more lenses are necessary, up to 6 for the typical 100:1 objective.
Making the objective "plan" needs a lot more lenses and thus Zeiss "plan" objectives were more expensive than Zeiss fluorites (non-plan). With more lenses there are more tolerances that add up and to offer Zeiss-quality everything has to be made to very close tolerances, increasing the price. If you want to make it "plan" but as a no-name seller don't have to offer faultless quality it comes a lot cheaper.

Some Zeiss West prices from 1974:

40:1 objectives, dry
achromat 84$
planachromat 337$
fluorite 329$
planapo 884$

In the 70s "plan" meant for Leitz perfectly plan over a field of 28mm. The cheaper NPL (normal-plan) offered planarity only over 24mm. Zeiss West offered planarity over 25mm.
A chinese "plan" objective will probably not offer more planarity than the basic eyepieces show, 18 to 20mm.

Bob

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Re: Chinese microscopes

#39 Post by Dave S » Fri May 24, 2019 4:12 pm

Hobbyst46 wrote:
Dave S wrote:...What I don't know, and perhaps you, or someone here can enlighten me, is the situation with microscope objective lenses. Are the achromats just basic single glass element construction, or are they doublets. Moving up to plan objectives, are these of triplet element construction. ??.
Here is a very good description:
https://www.olympus-lifescience.com/en/ ... bjectives/
Nikon and Zeiss sites also contain similar explanations.
That is an interesting read, thank you.

Certainly the apochromat objective, at least from the premium manufacturers is a complex multi element item. I wonder how the Chinese Plan objective construction compares.

Having said that, many of the premium brands are now manufactured in China, albeit under much stricter specs, and quality control.
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Re: Chinese microscopes

#40 Post by Dave S » Fri May 24, 2019 4:21 pm

MicroBob wrote:
Dave S wrote:What I don't know, and perhaps you, or someone here can enlighten me, is the situation with microscope objective lenses. Are the achromats just basic single glass element construction, or are they doublets. Moving up to plan objectives, are these of triplet element construction. ??
Hi Dave,
an achromatic closeup lens for a camera is a doublet. For microscope objectives usually more lenses are necessary, up to 6 for the typical 100:1 objective.
Making the objective "plan" needs a lot more lenses and thus Zeiss "plan" objectives were more expensive than Zeiss fluorites (non-plan). With more lenses there are more tolerances that add up and to offer Zeiss-quality everything has to be made to very close tolerances, increasing the price. If you want to make it "plan" but as a no-name seller don't have to offer faultless quality it comes a lot cheaper.

Some Zeiss West prices from 1974:

40:1 objectives, dry
achromat 84$
planachromat 337$
fluorite 329$
planapo 884$

In the 70s "plan" meant for Leitz perfectly plan over a field of 28mm. The cheaper NPL (normal-plan) offered planarity only over 24mm. Zeiss West offered planarity over 25mm.
A chinese "plan" objective will probably not offer more planarity than the basic eyepieces show, 18 to 20mm.

Bob
Thanks Bob, that is very informative, and nice when someone uses a real name as their 'user name', or if not, actually signs their post with it :)

On forums its a bit like a 'secret society', where people hide behind a fictitious user names, and are reluctant to disclose even what part of the world they live in.

I have nothing to hide, as you can see from my web site :)

https://davesimaging.wixsite.com/mysite
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ImperatorRex
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Re: Chinese microscopes

#41 Post by ImperatorRex » Fri May 24, 2019 4:31 pm

Hi Dave,
wow, really impressive fotos on your website. I like especially the Astro fotos - they are brilliant!
Jochen

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Re: Chinese microscopes

#42 Post by Dave S » Fri May 24, 2019 4:36 pm

ImperatorRex wrote:Hi Dave,
wow, really impressive fotos on your website. I like especially the Astro fotos - they are brilliant!
Jochen
Hi Jochen

Thank your kind comments, and I'm glad you enjoyed your visit.
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Re: Chinese microscopes

#43 Post by MicroBob » Fri May 24, 2019 7:10 pm

Dave S wrote:
Thanks Bob, that is very informative, and nice when someone uses a real name as their 'user name', or if not, actually signs their post with it :)

On forums its a bit like a 'secret society', where people hide behind a fictitious user names, and are reluctant to disclose even what part of the world they live in.
I prefer to address the person(s) I write to in a forum. My comment might be a reply on one or more specific posts and it is difficult to understand the thread when eyery post has to be seen as related to everything. I also find it leads to a more polite general athmosphere and better to read posts. But this is just me. I can also understand when people try to disclose as little as possible because the bits of information are connectible for outside persons. This is a bit difficult with my forename - no other real Bobs here in Germany and probably few elsewhere. :roll: Once I got a PM from somebody over one forum that was connected to a thread in another forum!

Bob

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Re: Chinese microscopes

#44 Post by Dave S » Fri May 24, 2019 8:11 pm

I would agree Bob, only a fool would disclose too much personal information on an internet forum, and yes there can only be so many Bob's and Dave's registered in one place.

Therefore, a non descript user name is sometimes essential, but it creates for much friendly atmosphere, when conversing with someone on a forum, if i can address them by the given first name, but then I'm a sociable sort of guy, and am not embarrassed by the name my parents gave me.

As for a general geographic location, I don't see that disclosing that you live in the UK, USA, Germany, or wherever, poses a personal data security risk. :lol:
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Re: Chinese microscopes

#45 Post by apochronaut » Fri May 24, 2019 10:22 pm

Dave S wrote:
apochronaut wrote:Since you have been involved with telescopes, I thought I would pass this along but you are already probably aware of this critical difference between microscopes and telescopes. It is one thing that many telescope users miss, when they switch over to microscopes and it can cause a bit of confusion because they are used to changing eyepieces to change the instrument's performance. You can't just do that without some careful thought and precautions on a microscope. I write this for any novice moving over from the telescope to the microscope, because I'm sure there are or are going to be some reading this thread.

To compare the two instruments directly as instruments to view something, each with an objective lens and an eyelens, the mode of use for each is somewhat reversed.

A microscope is actually several individual instruments attached to the same frame, depending on however many objectives it has. You could have an achromat, a fluorite and an apochromat, all in one stand, each coordinated to work with the same eyepiece but more often the degree of corrections of the objectives are similar and it is only the focal length or magnification that is different. The average microscope is basically 3 different size refractors all on one frame. Modifications of magnification and of corrective capacity are made by changing the objectives usually, and occasionally eyepieces too, as long as they are specifically coordinated to the objective being used or are a close acceptable match. In certain situations there are even reflecting objectives, so one can have a reflecting microscope as well. It is an array of different objectives on one stand that provides the user of a microscope, with a broader magnifying capability in general. Light gathering capacity and therefore resolving power is determined by the acceptance angle of an objective lens, plus the corrective capacity built into the coordinated optical combination.

With a telescope, the situation is generally reversed. You have to have several individual instruments and therefore objectives in their own frame, in order to equate to a microscope with a rotating nosepiece. It is an array of different eyepieces that provides the user of a telescope with a broader magnifying capacity, while using a single objective. Light gathering capacity and therefore resolving power is determined by the diameter of the objective lens, plus the corrective capacity built into the coordinated optical combination.
An excellent comparative explanation. :)

With telescopes the less well informed are attracted by the telescope in the high st shop, or mail order catalogue that says "200x magnification", which for astronomy is about a much use as a "Chocolate Fireguard".

In astronomy, we are about light gathering power, and resolution, magnification is secondary. Unlike with a microscope, we can't turn up the illumination

As you so aptly describe, a microscope can be several different optically spec'd instruments in one, depending upon how it is populated with optics.

With a telescope, we can only change the eye piece.

What does leave me somewhat amused, is you will find microscopes aimed at the hobbyist, some costing several hundred pounds, claiming magnification up to 2500x. Forgive me if I am wrong but this seems to be another "chocolate fireguard" scenario.
That is one of the fantastic marketing tricks that the lesser microscope manufacturers use to woo prospective buyers. It is particularly rife in the on-line microscope market and saturates the Chinese retail sector heavily. It is strictly aimed at the naive . Of course you can stack lenses ad infinitum to increase magnification as much as you want but empty magnification occurs at a certain point and renders any increase useless.

With decent achromatic objectives one can expect a magnification limit of about 1000X the N.A. marked on the objective.
With fluorite and apochromat designs it is a little higher. I use a factor of about 1100X for those but such factors as illumination/condensation , contrast and the precision of the optical alignment are also important deciding factors of just how far one can stretch the magnification of a system, and gain an increase in resolution.

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Re: Chinese microscopes

#46 Post by Dave S » Sat May 25, 2019 9:07 am

Following extensive on-line information gathering, I am currently considering the Swift range of Chinese microscope, as my 'dipping the toe in the water' venture into microscopy.

It seems that there are some 15 factories in China making microscopes, with online importers/retailers procuring from any one of these manufacturers, and then putting their own badge on them.

As such if you buy AmScope, Omax, Brunel, Apex, to name but a few, you can have no idea of the source, only that is in China, and there is probably little to choose between them.

Mitec are a long time established Chinese manufacturer of microscopes, and apart from marketing under the Mitec brand, also own the Swift, and National brands, producing microscopes under these brand names too.

As far as I can establish they do not sell their products to online retailers, who then put their own badge on them.

Yes, I know that Swift microscopes of the 1960's that were British made, could be found in many schools, and colleges, are not the same 'beast' as those now emanating from China, but at least they come from a known source, and come with a 5 year warranty.

On-line reviews, if they are to be believed, or written by informed people, are generally positive.

No decisions made yet, but of all the budget Chinese microscopes, the Swift is the only one with a traceable source, and if I buy direct from Swift-GB, albeit actually in China, or Amazon, with the latter I can just return it if unsatisfactory.

Maybe I will enjoy microscopy, as much as I enjoy my other hobbies, and if so, I will look to upgrade. If not, then I will not have lost a significant sum of money, and a local school will gain a microscope.
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Re: Chinese microscopes

#47 Post by MicroBob » Sat May 25, 2019 9:56 am

Hi Dave,
as far as I can remember Swift was an old/ancient british microscope maker. Later there was an american company importing japanese instruments like the FM-31 under this name, 1970s on.
Todays Swift offerings look different than the rest of the bunch, but they also seem to be located higer on the price scale. Here is a very dependable review in german language of the Swift M3-B Micro-Macro Field Microscope. https://www.mikroskopie-forum.de/index. ... ic=30109.0

Bob

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Re: Chinese microscopes

#48 Post by Dave S » Sat May 25, 2019 11:10 am

MicroBob wrote:Hi Dave,
as far as I can remember Swift was an old/ancient british microscope maker. Later there was an american company importing japanese instruments like the FM-31 under this name, 1970s on.
Todays Swift offerings look different than the rest of the bunch, but they also seem to be located higer on the price scale. Here is a very dependable review in german language of the Swift M3-B Micro-Macro Field Microscope. https://www.mikroskopie-forum.de/index. ... ic=30109.0

Bob
They were indeed Bob, and it was James Swift who started the company. I seem remember seeing Swift microscopes in the Biology class, when I was at school back in the 50's.

Swift (Mitec) do make some expensive microscopes, but also make some more towards the budget end (student/hobbyist), which they sell under their own Brand name (Swift), through e-bay, and Amazon.

I contacted Swift through Swift-GB on e-bay, to ask a question, and the reply came back from China, so it is clear that they trade directly from China via e-bay.

What attracts me, rightly or wrongly, is that they don't appear to supply companies that buy from unknown (to us the customer) sources, and then stick their own badge on it. This applies to the likes of AmScope, Brunel, GT Vision, Apex, and many others. That is not to say they are any better or worse than Swift, its just that they are from an unknown source.

I will keep 'digging', and will make my decision within the next couple of weeks. If I buy a Swift, or any another brand, I will give an honest opinion on it, based on what I find, and not based on rumour/hearsay, that derides the Chinese microscope, without ever having used one.

If I find it is optically acceptable, I will then go on to take some images with it, and post them here, so members can judge for themselves.

I wouldn't buy a budget camera, and lens, and expect it to perform like my Canon Pro Spec gear, and neither will I be buying a budget <£500 microscope, and expect it to perform like a Nikon, or Olympus professional model.
Last edited by Dave S on Sat May 25, 2019 11:11 am, edited 1 time in total.
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Re: Chinese microscopes

#49 Post by MichaelG. » Sat May 25, 2019 11:11 am

MicroBob wrote:Hi Dave,
as far as I can remember Swift was an old/ancient british microscope maker. Later there was an american company importing japanese instruments like the FM-31 under this name, 1970s on.
Brief potted-history of 'James Swift' here:
http://collection.sciencemuseum.org.uk/ ... on-limited

Also worth mentioning that Vickers used some of the Japanese 'Swift' objectives ... notably a rather nice 10x in a tapered barrel.

MichaelG.
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Re: Chinese microscopes

#50 Post by Hobbyst46 » Sat May 25, 2019 11:16 am

Dave S wrote:Here is another question :)

Given that most 4 objective microscopes come with 4x, 10x, 40x, and 100x (oil immersion) objectives fitted, is it better to swap the 100x (oil) for a 60x objective.

From what I read, unless you are interested in bacteria, the 100x would be rarely used, and that for most subjects, up to 400x magnification is adequate. Would you agree?
The important goal of a microscope is resolution, rather than magnification.
Accordingly, the important features of an objective are its numerical aperture and working distance.
The 100X usually means 100X1.25 or 100X1.3. An NA of 1.25-1.3 yields about twice the resolution of a 40X0.65 objective,
At the price of a shorter working distance, and the requirement for immersion oil.
The 60X0.85 objective, with NA of 0.85, offers a ~30% better resolution than the 40X0.65. These data are theoretical, in practice other factors also play a role.

If one thinks that the 100X will not be useful, I would take a 20X0.5 instead. Even better, start with a 2-3 Planachromate objectives instead of 4 achromates, If budget permits.
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Re: Chinese microscopes

#51 Post by MicroBob » Sat May 25, 2019 7:24 pm

Dave S wrote:Given that most 4 objective microscopes come with 4x, 10x, 40x, and 100x (oil immersion) objectives fitted, is it better to swap the 100x (oil) for a 60x objective.
From what I read, unless you are interested in bacteria, the 100x would be rarely used, and that for most subjects, up to 400x magnification is adequate. Would you agree?
It depends on what you want to observe. The n.a. of the typical oil immersion 100:1 is 1,3. This is twice of what the typical 40:1 has. For many amateurs this is not enough gain to start fiddling with the oil bottle. If you want to observe smaller diatoms or fungi spores this difference is very important.

For plancton use it is very attractive to have a 20:1 in the revolver.

A 60:1 with n.a. 0,85 an no correction collar is already very sensitive to cover slip thickness and depends on thin preparations. With an oil immersion this is less of a problem, thick cover slip, thin oil layer and vice versa. But some people like their 60:1 a lot.

For the 100:1 oil immersion the light and condenser setup have to be designed and adjusted well and the mechanical design of the microscope should be not too bad.

Bob

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Re: Chinese microscopes

#52 Post by Dave S » Sat May 25, 2019 8:24 pm

Very informative, thanks Bob.
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