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Opax Stereo Microscope, 1985?
Probably the first, and, for some, the last time they
peered down a microscope was in a school science class. It can be a memorable
experience and even the most cynical teenagers can’t fail to be
impressed by the intricacy and beauty of very small things, but all too often
that’s as far as it goes.
Part of the problem is that school microscopes are
generally robust and reliable designs but fairly conventional in nature.
They’re mostly monocular, with a single eyepiece, producing a flat
two-dimensional image, which is okay, but here’s a thought. How many students
might have been inspired to pursue their education, and a career in science if
what they saw through a school microscope was a spectacular view of the real
world, showing incredible depth and detail, in the kind of glorious,
mind-blowing 3D, that puts even the fanciest high-definition game visor to
Stereo microscopes are to optics what stereo sound is
to audio; it’s like comparing chalk with cheese and given that most of us have
two eyes (as well as two ears), it is hard to imagine why anyone would want to
use only fifty percent of one of their most important senses. To be fair,
unlike hi-fi, when it comes to stereo microscopes cost is a major consideration.
Even conventional monocular microscopes can be expensive and it follows that
stereo models of equivalent quality are going to cost at least twice as much,
and often a lot more, due to the added complexity. Sadly that means few of us
get to see what the micro world looks like in three dimensions, but they are
out there for those who care to look.
Stereo microscopes tend to be mostly
purchased by institutions and organisations where the cost-benefit equation
favours expensive, professional grade equipment. Eventually, though, these
things will be replaced, and one way or another scientific instruments that
once cost hundreds and sometimes thousands of pounds can end up in the general
marketplace, often selling for a fraction of their real worth.
This particular microscope’s backstory is unknown but
even though it’s not a top-notch, high-end instrument, it was probably bought
and used for a serious purpose. When new it would have cost a pretty penny,
definitely a great deal more than the 50 pence I paid for it at a car boot sale
in early 2014. In spite of that ridiculously low price it is a
pukka scientific instrument and you can tell that just by picking it up. It
might be small but it tips the scales at just under 1kg. That is mostly due to
the heavy-duty cast iron base and upright support arm, plus all of the other
metal and glass components; the only plastic parts are the tops of the
eyepieces and the two focussing knobs.
Each of the optical channels has a pair of prisms,
which is another reason why it is so compact. They’re housed inside the four shiny
Toblerone shaped metal caps. They work exactly like the prisms in a pair of prismatic
binoculars, which is basically two telescopes strapped together, giving a crisp
3D view of distant objects. It’s all about optical magnification and both
telescopes and microscopes depend on high quality lenses being spaced at
precise intervals in long lightproof tubes, but this has implications when it
comes to making them small and easy to use. The trick is to shorten the tubes,
and that’s where the prisms come in. They act as mirrors, bending the light
through right angles, so how far the light travels remains the same, but the
distance between the ends of the lightproof tubes is greatly reduced.
The two eyepieces on this model are mounted on swivel
joints, with a simple linking mechanism, so they can be adjusted for
inter-ocular distance – in other words, how far apart your eyes are. This Opax
came with a set of 6 interchangeable eyepieces, which slide into the top of the
two chrome tubes. These give a choice of three magnifications, 10x, 30x and
45x. Focus is set by twiddling the knobs on the side. They’re connected to a
rack and pinion mechanism that moves the whole eyepiece assembly up and down.
The platform, or ‘stage’ beneath the lower objective lenses is where you put
whatever it is you are looking at. It’s a slab of ground glass, with room
underneath for a light source, so it can be illuminated from below (if the
specimen is transparent) or above. A
pair of springy chrome plated fingers is attached to the base, behind the
stage, to stop slides and thin objects from slipping around (or getting away…).
The quality of construction is outstanding and it was
clear that it had been well looked after. All it needed to get it looking like
new was a wipe over with a soft cloth. At some point this one had become
separated from its wooden storage box, and the lens in one of the eyepieces has
some stubborn crud on it and it will need removing. Otherwise optical performance
and general condition is almost as good as the day it was made,
What Happened To It?
Opax appears to have only made microscopes but
strangely there is almost nothing about the company on the web. It is really
unusual for a manufacturer to just vanish without trace; even if it had been
bought out or gone bust you would expect some sort of record, but in this
instance I drew a complete blank. If anyone can fill in the gaps please let me
The only certainty is that Opax was a Japanese
company, probably operating between the early 70s and late 80s, though that’s a
guess. It’s based solely on an aggregate of the manufacturing dates mentioned
in the few microscopes that have appeared on ebay and other websites in the
last few months. There seems to have been at least three monocular microscopes
and three stereo models. Prices vary a lot but monocular types with their
original boxes typically sell for between £20 and £50 and in keeping with the
extra optics, stereo microscopes start at around £60. The brand is clearly not
in the top echelon, but judging by the prices and the relatively limited amount
of information available it would seem that Opax are quite well regarded and if
you come across an instrument in good useable condition selling for markedly
less than those appearing on ebay it should turn out to be a reasonably sound
investment. If it’s a stereo model, so much the better, and prepare to be
First seen 1985?
Original Price £?
Value Today £20
Features Stereo optics, twin prisms (per optic), interchangeable
eyepieces (10x, 30x, 45x), rack & pinion focussing, ground glass stage,
Power req. N/A
Dimensions: 200 x 108 x 98mm
Made (assembled) in: Japan
Hen's Teeth (10 rarest): 8