Infinity corrected microscopes

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ivangallego24
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Infinity corrected microscopes

#1 Post by ivangallego24 » Fri Aug 30, 2019 6:45 pm

Someone would tell me what advantages and disadvantages these microscopes have over others, and the differences as well.

PeteM
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Re: Infinity corrected microscopes

#2 Post by PeteM » Fri Aug 30, 2019 6:52 pm

The question has been answered a few times. Might want to search the posts, then come back with detailed questions?

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Re: Infinity corrected microscopes

#3 Post by Dave S » Fri Aug 30, 2019 6:56 pm

I'm no expert Ivan, but I am led to believe that in terms of image sharpness, and resolution, there is no difference between infinity corrected optics, and 160mm RMS standard ones.

However, again, as I am led believe, a microscope with infinity corrected optics is far more flexible when come to 'reflected light', and Florescent microscopy.

I also believe that each manufacturer matches the whole optical system to their own specification, and as such you can only use their objectives, whereas you can put any brand of 160 RMS objective, on any 160mm tube scope

That said, the are some real experts on this forum, you will be able to give a more definitive answer.
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Re: Infinity corrected microscopes

#4 Post by Roldorf » Fri Aug 30, 2019 7:53 pm

According to Zeiss:-

Infinity-corrected microscope optical systems, which have overtaken the microscope market, are designed to enable the insertion of auxiliary optical devices, such as vertical illuminators, filter cubes, and intermediate tubes, into the optical pathway between the objective and eyepieces without introducing spherical aberration, requiring focus corrections, or creating other image problems.

It of course also allows manufacturers to 'lock down' their market so that you must purchase their objectives to use in their systems.
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apochronaut
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Re: Infinity corrected microscopes

#5 Post by apochronaut » Sat Aug 31, 2019 3:41 am

If it were just a case of comparing two BF microscopes; one with a fixed tube length and one with infinity correction, then neither would necessarily be better based solely on the optical system.

However, as microscopy has advanced over the years, an increased number of techniques designed to increase contrast or enhance the microscope image in some way have emerged. Infinity correction allows for multiple techniques to be used without affecting the image quality or parfocality, whereas with fixed tube systems , some quite complicated compensation needs to be installed in order for certain image enhancing techniques to be employed. For this reason infinity corrected microscopes can theoretically provide a microscope with better optical capability for less cost.

The development and improvement of fixed tube systems has halted because infinity correction is the system of choice for all manufacturers. Therefore, any subsequent improvements in microscope optics will take place within the context of infinity correction. This has already been the case for close to 30 years.

There is no less compatability between infinity optical systems than between fixed tube systems. Fixed tube optics required compatible eyepieces to be used , so more often than not , even though the objectives from two different makers could be used on an R.M.S. standard fixed tube stand, the entire optical system would need to be coherent for the performance to be adequate, so eyepieces and objectives would be needed as a unit.
In the case of infinity optical systems, the tube lens takes the place of the eyepiece in requiring optical conformity. Several manufacturers at least, have acceptable conformity since the objectives in many systems have the same level of corrections, so D.I.N. infinity objectives from Reichert, AO and Olympus are generally compatible. Only a small error in magnification exists when mixing Olympus with the two former brands. Early Leica optics, since they are in fact AO/Reichert derived are also perfectly compatible.

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75RR
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Re: Infinity corrected microscopes

#6 Post by 75RR » Sat Aug 31, 2019 5:24 am

For the amateur microscopist on a modest/limited budget the main difference is cost.

High end top of the range objectives, the only ones you will likely see any discernible difference on (assuming you have setup the microscope perfectly) will cost you several thousands rather than several hundreds.


There are some brands that began constructing infinity objectives a lot earlier than others, while these relatively old objectives are more modestly priced, they are hardly cutting edge - and not worth a move to infinity solely on their account.

As to compatibility between major brands, it is much more limited than has been suggested.


There will come a time when the market is awash with used quality infinity microscopes as Universities and Research Centers upgrade their instruments.

At that time the prices should be within the reach of amateur microscopists.

I look forward to that day, but it is not here yet.
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Re: Infinity corrected microscopes

#7 Post by Hobbyst46 » Sat Aug 31, 2019 7:18 am

With modern infinity research grade microscopes even the objective tbreads are not the same among brands.
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Re: Infinity corrected microscopes

#8 Post by ImperatorRex » Sat Aug 31, 2019 7:46 am

Maybe one reason for the infinity system that not has been mentioned: In particular, infinite system photography offers the possibility of directly imaging the intermediate image on the sensor - without relay optics, photo eyepieces or projective lenses. So an additional source of dust/dirt is eliminated from the optical pathway.

Personally as a lover and primarily interested in equipment and technology I will probably will never get calm, without entering the infinity world. The good thing is that the components - including DIK - are quite easy to find (respectively ebay USA). It will cost a lot of money, but over the time a top device will come together :-)

Howevery, if it's primarily about the biology and the objects, the finite systems offers quite the same with a much more reasonable budget (buying used equipment).

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Re: Infinity corrected microscopes

#9 Post by Scarodactyl » Sun Sep 01, 2019 5:22 pm

ImperatorRex wrote:Maybe one reason for the infinity system that not has been mentioned: In particular, infinite system photography offers the possibility of directly imaging the intermediate image on the sensor - without relay optics, photo eyepieces or projective lenses. So an additional source of dust/dirt is eliminated from the optical pathway.
Do you have this reversed? You can put an image directly on the camera sensor with a finite system and no intermediate optics, but an infinite system requires a tube lens.
In either system type you can theoretically do direct projection without extra optics (beyond the tube lens if needed), but it is only sometimes practical depending on the microscope system. Projection eyepieces can be really annoying, since a tiny bit of dust will show up very noticeably on your pictures. But most trinoc ports won't let you put the camera low enough to get an image directly on the sensor, and of course you'd be missing eyepiece corrections if any.
I'll admit I've been pondering modifying my nikon alphapot's trinoc to do direct projection, though I haven't looked too closely at it yet.

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Re: Infinity corrected microscopes

#10 Post by apochronaut » Mon Sep 02, 2019 2:12 am

75RR wrote [/quote]
There are some brands that began constructing infinity objectives a lot earlier than others, while these relatively old objectives are more modestly priced, they are hardly cutting edge - and not worth a move to infinity solely on their account. [/quote]



How do you know this?

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Re: Infinity corrected microscopes

#11 Post by 75RR » Mon Sep 02, 2019 5:13 am

apochronaut wrote: "How do you know this?"

The argument in favor of infinity objectives rests on the fact that they are cutting edge, i.e. coating and design and computerized manufacturing technique give them an edge over older (usually 160 objectives).

If an objective was designed and built before this time it is not cutting edge and therefore does not benefit from this argument.

As an infinity objective on an infinity microscope it does however suffer from the lack of compatibility that affects infinity microscopes.


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Re: Infinity corrected microscopes

#12 Post by ImperatorRex » Mon Sep 02, 2019 5:44 am

Scarodactyl wrote:
in either system type you can theoretically do direct projection without extra optics (beyond the tube lens if needed), but it is only sometimes practical depending on the microscope system.


Thanks Scarodactyl. As far as I know the issue with the finitey system is that oculars are required to apply the spherical and chromatic correction. So direct projection will suffer from such not corrected errors. The infinite system will not have this issue, since tube lense is in the light path that applies the correction. Physically accessing the intermediate image is another issue...as you have stated.

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Re: Infinity corrected microscopes

#13 Post by Scarodactyl » Mon Sep 02, 2019 6:38 am

Nikon's -phot line and apparently many Chinese finite ones (plus almost every stereo system of course, they don't matter foe this discussion but they're probably why I had it in mind). don't have significant compensation in the eyepieces, so there are a few cases it can work.

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Re: Infinity corrected microscopes

#14 Post by apochronaut » Mon Sep 02, 2019 12:16 pm

75RR wrote:
[\quote] The argument in favor of infinity objectives rests on the fact that they are cutting edge, i.e. coating and design and computerized manufacturing technique give them an edge over older (usually 160 objectives).

If an objective was designed and built before this time it is not cutting edge and therefore does not benefit from this argument.

As an infinity objective on an infinity microscope it does however suffer from the lack of compatibility that affects infinity microscopes.[\quote]

I have been fortunate enough to have actually used a broad range of microscope systems :160mm, 170mm and several infinity systems Zeiss, Olympus , Reichert, AO and the modified version of B & L. Computer modelling in optics design began before 1985. That is now 35 years ago at least, so ray tracing and the like was being used , even on mid-80's fixed tube systems but just at the time that they were becoming obsolete. By comparison, the circa 2005 2.5X .075 planfluor objective I recently purchased for 90.00 is part of a family of objectives that go back to around 1970. It, for sure, has benefited from state of the art production and I am happy to include it in an older system, and could in fact include it in a system as old as 58 years, if I so chose to. Any, 160mm optics in that category out there?

A more salient value of infinity correction is their modularity. Infinity corrected systems can be made very modular, allowing the user , much greater flexibility in retrofitting and upgrading into the future, plus the obvious value that any objective made for the system is compatible with any intermediary piece, made for the system

Regarding compatability. That is a choice of the manufacturers. As of today, Reichert, Olympus and some Chinese infinity optics are compatible if one accepts a 10% differential in magnification. Older AO can be added to that group, by adding one component alteration, something AO/Reichert included in design paramaters. It seems that in the modern world of competiton coupled to the design revolution that infinity correction has allowed manufacturers to enjoy, standardization isn't in the cards but for a basic BF microscope, there is at least some. I'm not sure standardization is what it is all about , though .

Standardization never really existed anyway, because the manufacturers only wanted it when it would benefit their business interests. The same as it is now. Zeiss and Leica were always at loggerheads, with each one peeking out of their silo and keeping their optical designs far enough apart that one would have to be a Rube Goldberg , in order to harmonize anything. Sure , there were a lot of 160mm tube systems around but how easy did that make moving optics around? It only did in the early days, pre- W.W.II, when Huygens eyepieces were widely used and their general overall corrections could be relied on to be compatible with other manufacturer's objective requirements. Even then, companies frigged around with the corrections on Huygens eyepieces. You can't use some Huygens on anything but the intended, unless you happen to have a rainbow fetish. Then, there was parfocality and D.I.N. You can't really swap 160mm optics from stand to stand, unless you swap the whole lot and the eyepieces too. Then there are the intermediary pieces. Varying back focal planes can easily throw the corrections with different objectives out the window.
By the time the world indicated that it really, really needed wider fields of view and a whole post W.W.II generation of proprietary wide field optics started to emerge, any idea one might have that there was a cozy club of standardized microscope manufacturers in existence, eagerly scratching each others backs, is just a misconception. The standards sort of existed but by and large the manufacturers were clawing at a pile of money that had too many takers. The cream doesn't always rise to the top, sometimes it is the scum that does. One way of getting at , at least some of that pile, was to exert your independence and make sure your customers were your customers and the way that could be ensured was to have an optical system that was intricately tuned to accept no imposters. And how did you sell them a new microscope? Make the old one obsolete but keep enough of it current , so that a new purchase would be very very tempting. A little kickback never hurts either.

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