[Title fragment 1.1] [Title fragment 1.2] [Title fragment 1.3]
[Title fragment 2.1] [Title fragment 2.2] [Title fragment 2.3]
[Title fragment 3.1] [Title fragment 3.2] [Title fragment 3.3]

The MBS-10 stereo microscope (II)

As stated already in the previous issue we would like to amend some ubiquituous misunderstandings concerning the Russian MBS-10 stereo microscope.

Manufacturer is by no means the well-known LOMO company in St. Petersburg but instead the "Optical Glass Factory Lytkarino" (MBS-10 error I). Lytkarino is situated far away from St. Petersburg - it is close to Moscow. And a glance at the circular red Lytkarino emblem on the MBS-10 body will convince you that it is obviously quite different from the LOMO logo. We think that the wide-spread misunderstanding is obviously stemming from the fact that LOMO had some kind of optical distributor function towards the West which included the sale of Lytkarino products.

[ The MBS-10 stereo microscope ]

The MBS-10 stereo microscope

A fully equipped MBS-10 will come with a styrofoam box containing spare bulbs and various types of alternative eye-piece pairs. Above all you should make sure that the splendid "14x" eye-pieces with a paradise-like field of view are included when buying a MBS-10 microscope.

The red arrow in the image is pointing towards a screw which fixes the stereo head. Take care with the second screw below: it is holding the main objective which will inevitably follow the force of gravity when unlocked.

Thanks to the internal 0.6x to 7x objective magnification changer and in combination with the 6x to 14x eye-pieces an overall magnification range between 3.6x and 98x can be reached. This range can even be further extended downwards and upwards by using optional 0.5x and 2.0x objective lens attachments which can be fixed below the main objective. But we think that those attachments will make sense only in a few very special situations. Be aware that any additional front lens will have a tendency to deteriorate the fine optical correction quality of the main objective.

As a consequence an overall 196x maximum magnification will be technically feasable, just by combining the 2x front-lens attachment with magnification changer position 7x and eye-pieces 14x. But on this pathway you will end up with an "empty" magnification, i.e. an over-magnification lacking additional visual detail. The Numerical Aperture (the resolving power) of the MBS-10 main objective is reported to be in the range of 0.8. But, as a rule of thumb the overall magnification of an optical system should not surpass the 1,000fold value of the Numerical Aperture. So everthing beyond a ~ 80x magnification will be in fact over-magnification. And please keep in mind these are purely physical limits, i.e. limits encountered with any microscope brand, also the most expensive ones.

This might be one of the reasons why some web reviews tend to depreciate the MBS-10 microscope because of lacking visual and photographic image quality (MBS-10 error II). It should be kept in mind that even for most professional purposes a MBS-10 in good working order will be perfectly adequate. Furthermore there is no doubt that for perfect image quality in the macroscopic range a completely different system should be preferred, namely a combination made up of a modern CCD chip peeking directly through a bellows system and a high-quality repro objective onto the object.

As far as the MBS-10 microscope is concerned our clear favourite for visual inspection is the 2x objective plus 14x eye-piece combination. Of course, the other magnifications are usable as well, but with some minor drawbacks.
When looking inside the MBS-10 you will notice that the magnificent image quality of the 2x objective / 14x eye-piece combination can be explained by the fact that no intermediate lenses are used in this particular combination.

[ MBS-10 stereo microscope magnification changer ] [ MBS-10 stereo microscope magnification changer ]

View into the heart of the MBS-10 microscope (stereo head removed): Magnification changer position "7x"

Magnification changer position "2x", without intermediate lenses. The latter combination is our favourite and most recommended one.

A properly adjusted and clean MBS-10 microscope in combination with 14x eye-pieces will be appreciated as a wonderful instrument by an estimated 98% of all microscopists. Due to the extremely wide field of view you will feel like an eagle flying over the tardigrade garden! But - and this happens from time to time - if the image impression is dizzy or ghost-like, you might be sitting in front of a misaligned microscope in need of repair.

We think that those DIY repaired and misaligned instruments are the main reason for internet statements complaining about the MBS-10 image quality in general and related claims that an instrument made by the famous western L ...., W ... oder Z .... companies would have a tremendously higher image quality and resolution. This has to be considered as MBS-10 error III.

Moreover it should be kept in mind that the MBS-10 microscopes appear to have been produced in identical manner over several decades. So many instruments offered nowadays are old and show signs of heavy use. Many of them stood on rainy flea markets and were repaired by the less qualified people. Over the years we have seen many MBS-10 microscopes in poor condition: brutally broken focus knobs, deformed stands, dust-loaded optics etc.

On the other hand our own MBS-10 microscopes appear to be tough: in constant use since decades, never under a dust cover, never in service or repair - still in a perfectly usable condition.

So when buying a MBS-10 on Ebay we recommend that you should thoroughly check the description and the seller profile. Two typical but still repairable MBS-10 defects might be:

Damage 1: Partially scratched main objective. During careless use the main objective might have fallen down on the slide holder clips. This could have caused a partial breakdown of the main lens into cracks, chips and a pickled glass surface. When coming across such an objective one might think that it might be unrepairable. But we found out that sometimes it will be sufficient just to rotate the main objective clockwise or counter-clockwise so that the optical path will not go through the pickles but through a well-preserved area (you see, the cross-section of the main objective lense is quite large, most of it remains unused). Of course we are aware of the grim old man in the laboratory suit pointing out at this very moment that even a single scratch on the objective will turn a microscope "useless for scientific purposes". Possibly, sometimes, yes. But we have seen at least one MBS-10 where this rotation of the main objective drastically improved the image quality. So, before disposing of your scratched main objective, think about this potential solution.

Damage 2: Misaligned prism head (ghost images, double image impression, headache optics). This is mostly repairable - if the prisms themselves are still intact:
The cover of the stereo head can be easily loosened by means of a normal screwdriver. But take care not to harm the pupil-distance adjustment mechanism when lifting the cover. Just have a look at the following images before, so you will understand how the lever is linked to the stereo head.

[ MBS-10 alignment 1 ]

Three slotted screws are fixing the cover of the stereo head.

[ MBS-10 alignment 2 ]

The eye-piece tubes can be easily removed just by counter-clockwise rotation.

[ MBS-10 alignment 3 ]

But please take care not to hurt the pupil distance adjustment mechanism. Just try to loosen the cover by soft multi-directional movement, without applying undue force.

[ MBS-10 alignment 4 ]

The read arrows are marking the four slotted screws which are fixing the prisms in hopefully well-aligned position.

The alignment procedure itself is not complicated. Just proceed by slightly loosening the four screws which are holding the prisms in place. It is not necessary to completely loosen the prisms, just partially, in a manner that the prisms can be laterally displaced on the horizontal support. For alignment control you will need to temporarily mount the tubes again. Then the prisms are moved in x-y-direction until the ghost image and related problems are gone. In the end you can fix the prism screws again (softly! Without cracking the glass!). During the procedure you might remove the most extreme dirt by means of a soft cloth. But do not overreact or overclean.
In the end, when everything is back in place you should be able to see even the tiny Echiniscus tuns in an acceptable image quality, like on the two photomicrographs below:

[ Tardigrade "tun" on a dry moss cushion 1 ]

A tardigrade "tun" on a dry moss cushion. Total view, photograph made by means of a MBS-10 microscope with photographic attachment. Image width 12 mm.

[ Tardigrade "tun" on a dry moss cushion 2 ]

Detail of the same image (just cropped from the image above).
The tun measures about 1/20 mm in length.

Please accept one more piece of advice: the inbuilt illumination of the MBS-10 microscope is clearly outdated and moreover possibly not perfectly safe when seen with the eyes of one of our professional electricians. But meanwhile there are many LED lights available with an acceptable light intensity and colour rendering. We are successfully using an IKEA "Jansjö" swan neck LED lamp bought for less than 10 US$. Of course a classical 150W microscopy cold light source will still have some advantages like light intensity regulation knob, filtering wheel and even more light output. But, at a price. And you won't notice in the photographs.

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
Water Bear web base is a licensed and revised version of the German language monthly magazine  Bärtierchen-Journal . Style and grammar amendments by native speakers are warmly welcomed.

Main Page