Compatibility of new eyepieces

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George
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Compatibility of new eyepieces

#1 Post by George » Fri Dec 30, 2022 12:20 pm

Hello,
I'm thinking of getting the 380T swift microscope. Ηowever because I have glasses and it comes with normal eyepieces, I want to get a pair of glasses compatible eyepieces (like these: https://www.amazon.de/-/en/dp/B005OMS2M ... _lig_dp_it) but I have noticed that the diameter of these is 20mm instead of the normal 18mm. Would the different diameter and widefield be a problem?

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Re: Compatibility of new eyepieces

#2 Post by viktor j nilsson » Fri Dec 30, 2022 12:45 pm

22mm is the width of the image circle, not the tube width.

But these are for 30mm tubes, not 23.4mm. So they will only fit on superwide heads, or many stereo microscopes.

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Re: Compatibility of new eyepieces

#3 Post by BramHuntingNematodes » Fri Dec 30, 2022 2:05 pm

I had thought those glasses meant a large amount of relief, more than 20mm for example. The stock eyepieces with the swift may already be able to accommodate glasses. It is a popular model, so someone probably could say if this is true.
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George
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Re: Compatibility of new eyepieces

#4 Post by George » Sat Dec 31, 2022 4:40 pm

viktor j nilsson wrote:
Fri Dec 30, 2022 12:45 pm
22mm is the width of the image circle, not the tube width.

But these are for 30mm tubes, not 23.4mm. So they will only fit on superwide heads, or many stereo microscopes.
Thanks for the answer,
I found a different eyepiece with a 23.2mm diameter (but I can't find a 23.4mm).
Would this work? https://www.amazon.de/-/en/dp/B07NMLYC6 ... g_dp_it_im

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Re: Compatibility of new eyepieces

#5 Post by viktor j nilsson » Sat Dec 31, 2022 6:31 pm

George wrote:
Sat Dec 31, 2022 4:40 pm
viktor j nilsson wrote:
Fri Dec 30, 2022 12:45 pm
22mm is the width of the image circle, not the tube width.

But these are for 30mm tubes, not 23.4mm. So they will only fit on superwide heads, or many stereo microscopes.
Thanks for the answer,
I found a different eyepiece with a 23.2mm diameter (but I can't find a 23.4mm).
Would this work? https://www.amazon.de/-/en/dp/B07NMLYC6 ... g_dp_it_im
Sorry, I mistyped.

I very much doubt that those are going to be any better than the ones included with the 380T. They're okay, not great. Haven't heard anyone complain about the eyepieces shipped with the 380T, I would be surprised if they didn't work okay with glasses. Most eyepieces do these days. You should definitely try them before buying anything different.

If you end up wanting to buy new eyepieces I highly recommend this style:

Image

They are fantastic value for the money. Some tests here: https://www.photomacrography.net/forum/ ... 4&start=15

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Re: Compatibility of new eyepieces

#6 Post by blekenbleu » Sat Dec 31, 2022 8:24 pm

The Swift 380T is a finite (160 tube length) microscope; except for Nikon since 1980 or so,
most finite microscopes depend on eyepieces to help correct objective aberrations.

I also own and recommend those WF10X/22 high eyepoint eyepieces, but they provide no corrections
and thus work best for modern infinity microscopes and finite Nikon Biophots and newer.
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Re: Compatibility of new eyepieces

#7 Post by viktor j nilsson » Sun Jan 01, 2023 8:33 am

blekenbleu wrote:
Sat Dec 31, 2022 8:24 pm
The Swift 380T is a finite (160 tube length) microscope; except for Nikon since 1980 or so,
most finite microscopes depend on eyepieces to help correct objective aberrations.

I also own and recommend those WF10X/22 high eyepoint eyepieces, but they provide no corrections
and thus work best for modern infinity microscopes and finite Nikon Biophots and newer.
Yeah, but the big makers have been designing compensating systems where the aberrations of objectives and eyepieces are designed to cancel each other out. As far as I can tell, the Swift 380T and other Chinese microscopes are not designed according to this principle, and are not sold with specific eyepieces. So although there might be some eyepieces out there that happens to improve the performance of these objectives, Swift won't be able to tell you which ones these are. And as far as I can tell, most Chinese microscopes are shipped with neutral or very weakly compensating eyepieces. So unless you want to experiment with different compensating eyepieces from Leitz, Olympus, Zeiss etc to find a perfect match, I think the 10x/22 will be good enough for the 380T.

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Re: Compatibility of new eyepieces

#8 Post by apochronaut » Sun Jan 01, 2023 3:41 pm

The 380T uses the most basic R.M.S. objectives. Simple achromats made to a formula in the hundreds of thousands. They require correcting eyepieces. Eyepieces like the WF10X/22 pictured, just as Viktor says and in my experience provide almost no correction and work well in infinity systems requiring neutral corrections. They are very good eyepieces but I suspect used in a microscope using modest 160mm achromats, that Blekenbleu is closer to the truth. I have a feeling that they will under correct and that despite gaining superior glasses on performance the quality of the image towards the periphery will suffer.
The objective eyepiece combination in the 380T yields an 18mm f.o.v. It is likely that is about all possible with those objectives. Any more and the peripheral corrections will likely fall right off, so additionally choosing an eyepiece with a 22mm field of view would likely really challenge those objectives.

I think George, that your best bet is to go for those W.F.10X/18 glasses on eyepieces( with the little spectacle image)from your second link. Those will be correcting eyepieces. You will also find that the 25X eyepieces offered in the kit will be useless. Best used in reverse as a high power magnifier.

It is important for you to know that changing eyepieces from one microscope to another or adding an eyepiece of unknown origin, is always fraught with some risk. Each microscope system is optically unique except for a few instances and eyepieces are uniquely designed with the utmost accuracy to optimize the image arriving at it over the entire visual field. Except in a few cases all of that risk takes place roughly over the outside 25% of the image. Almost any eyepiece will provide a good image over the central roughly 50% of the field but only eyepieces with the right amount of correction or compensation( the opposite of correction) to match the objective's needs will optimize the image right out to the field stop.
The correction requirements of older simple achromat designs are the easiest to predict though, because they have been around for so long.

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Re: Compatibility of new eyepieces

#9 Post by viktor j nilsson » Sun Jan 01, 2023 4:09 pm

apochronaut wrote:
Sun Jan 01, 2023 3:41 pm

I think George, that your best bet is to go for those W.F.10X/18 glasses on eyepieces( with the little spectacle image)from your second link. Those will be correcting eyepieces.
Are you sure about this? I think I have an identical pair lying around somewhere, I have no recollection at all that they were correcting.

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Re: Compatibility of new eyepieces

#10 Post by apochronaut » Sun Jan 01, 2023 7:28 pm

Very neutral eyepieces from China are a relatively new thing and exclusive to infinity corrected microscopes, unless I have missed a very high end recent 160mm model but one such would be a rare oddity

In the case of China, due to it's planned economy there is a large scale concerted effort to harmonize production in all sectors of consumer manufacturing, so in manufacturing, China can be viewed as one or at most several companies in each sector, rather than myriads of companies in a big country. This is in regards to their own branding outside of the contract work they might be doing for foreign companies.
The Chinese factories exist to supply raw parts to numerous assembly operations and in most cases the parts are cosmetically customized in order to appear different brands or business partners but in reality they perform the same. Motic and one or two others may be an outlyer in this due in Motic's case to their Hong Kong origin but even they are free to pick from the supplier pool. Your WF10X/22 eyepieces for instance are a quite new design but cleverly so, to a standard 10X/26 design with neutral corrections made cost effective through the efficient production of probably not too far off of 100,00 units. They can receive a 30mm tube, a 23.2mm tube or any other tube threaded in the bottom under a maximum and any field stop size under it's flat field maximum so it is one size fits all eyepiece. . Only one eyepiece design is necessary to match the requirements of any objective/telan lens combination engineered to produce an optimally corrected image. They have spun an entire country wide and in fact world wide plethora of NIS clones. There is a similar onslaught of Olympus clones, all the same optically but they look different. I have not seen too many, if any that are less than a 20mm field of view (f.o.v.)

All of the 160mm tube length microscope designs out of China are obsolete but sufficently cheap to produce, especially 25 years on to be valuable as a guaranteed revenue machine. There is a huge market world wide for cheap microscopes. Those optics have probably been produced in the hundreds of thousands, if not millions. You can probably find them in some schools in the Central African Republic, unless the Wagner group has stolen them all. Unless a 160mm tube Chinese microscope is plan and of the most recent production it will require peripheral correction in the eyepiece(s). That's why Huygens eyepieces became so popular. They are naturally over corrected and so impose a small amount of correction on the under corrected image emanating from a cheap achromat. Huygens eyepieces only lost favour due to possessing a narrow field, and while still available to this day due to their economy, they have been slowly replaced in better microscopes by wider field designs that provide wider, flatter fields with anywhere from similar to a Huygens' level of correction to better correction but never possibly perfect when used with an achromat. The eyepiece can only do so much. All of those wider field eyepiece designs were originally between 16 and 19mm f.o.v. with the bulk of them around 18mm. Irregardless of design, in order to make the best of an achromat the eyepiece must be a correcting type. This is not necessarily the case with certain modern plan achromat designs where the eyepiece can be anywhere from neutral to compensating. This was the revolution, in addition to infinity correction, that both Bausch & Lomb and AO initiated in the early 60's : each had a universal objective series that could be brought to the same degree of correction, whether achromat or apochromat and the same eyepiece used for all of them. The rest of the pack at the time were still using correcting eyepieces for achromats and compensating eyepieces for apochromats.
In China, no such universality throughout an objective range in fact compensating eyepieces if not were necessary because I have never seen a 160mm Chinese apochromat. Since you have those Chinese 18mm f.o.v. , glasses on eyepieces, have a look and see if they exhibit a blue halo around the field stop?
Even the CFWE 10XA/18 Nikon eyepieces exhibit a tiny amount of blue halo, indicating that they are not in fact neutral but slightly correcting.

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