World's smallest microscope? (II)

Meanwhile we received some hints to a serious microscope-tinyness competitor. It is called "Microscope Gaudin" and shown on a fabulous website called Le Compendium, run by Albert Balasse. In fact, the Microscope Gaudin features a height of 2.4 cm, thus being 3 mm lower than the Leitz Algensucher. On the other hand the Microscope Gaudin has a rather broad top flap making it bigger in volume ;-). But seriously, both of them are really small instruments.

We had promised to present the Leitz Algensucher in more detail and will continue on this pathway:

Fig. 1: The Leitz "Algensucher", an extremely tiny transmitted light microcope. Height 27.1 mm, maximum diameter 20 mm, diameter at base level ca. 16 mm. Weight 19.8 g

We had already shown the minute eye-lens previously:

Fig. 2: One of the world's smallest eye-lens openings - measuring merely 0.72 mm!

Now let's look at the backside of the eye-lens which is cleanly fitted in a brass housing:

Fig. 3: This is the complete optical system, as seen from the inside. Minimalistic microscopy! The free diameter of the (bigger) object-oriented lens side is measuring ca. 2.7 mm. The eye-side opening becomes visible in this perspective as well (appearing as a smaller bright disc). Due to the small entry iris much of the critical side rays are cut off and a better overall image quality is reached.

The geometry of the lens is hemisperical. On the basis of an assumed total diameter of 3 mm and a height of 1.5 mm a magnification of roughly 100x can be expected - which is clearly within in the Leeuwenhoek liga.
As microscopists you will be interested in the practical outcome and usefulness. In order to clarify this point we prepared a photomicrograph of an Amaryllis pollen specimen as seen through the Algensucher:

Fig. 4: Amaryllis pollen, as seen through the Leitz "Algensucher" mini microscope. Camera: Sony Nex-5N, illumination by means of a transparency viewer (as a background illumination). These pollen particles can serve as a kind of ruler or calibration scale because their length is close to 0.1 mm (whereas typical tardigrades range between 0.3 and 0.5 mm in length).

Of course we can compare this image quality with the one gained by means of a standard benchtop microcope:

Fig. 5: Amaryllis pollen, photographed through a standard benchtop microscope equipped with a 20x/N.A. 0.65 objective

The big microscope is delivering a better overall image quality, but the perceivable object characteristics look about the same as in fig. 4.

Still there are two important questions remaining:
(1) How to prepare the samples when taking into account that the tiny Algensucher housing apparently has no side slits for slides?
(2) What would be the visual impression when looking at a tardigrade?

Please stay tuned. We will come up with answers in the June issue.

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
The 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.

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