After working, teaching, and playing with
most of the student and benchtop sized microscope makes and models
from the mid 1960s to 1990s that were available in the USA, my favorites are the various versions of
the Olympus BH2. Certainly the other major brands have made very good
microscopes with very fine optics, but in the 1980s, none matched the
combination of modern style, ergonomics, engineering, quality, optics,
durability, and smooth operation that characterize the various BH2 models.
Olympus sold a huge number in the 1980s and 1990s; many are still in service,
and parts remain abundant. Some other makers copied the general design and
styling of the BH2 and its smaller sibling the CH2, even long after after
Olympus moved on to their CX and BX designs. Cheap imitations might work OK for
a while, but there is no substitute for quality, nor for the pleasure of using
so excellent a microscope.
In my hobby of renovating microscopes, I enjoy collecting and working on all brands and types that are polarizing, and also the other Olympus models. If only I had space and finances, the best examples would stay on my shelves to admire and use. However, when I am happy with how they look and work, most are sold so I can afford to buy some parts for the next project -- several of which are always awaiting! I have also taken and collected a lot of Olympus microscope photos and documents, and they are posted here as a way to keep them organized and accessible. Please respect that they are for private, personal use only, not for sales or commercial purposes.
BH/BH2/CH/CH2 microscopes are relatively easy to service, and their high quality means they can stay in great condition even after years of use. I ought to know, as I have had more than 50 different "pre-owned" examples (lost count some time ago) in my shop. Photos of some of my Olympus microscopes and their parts, and my collection of documents and web links about Olympus BH2, CH2 and related models, are shared on this page. Also see my wonderful BH2 BHSP and other descriptions of Olympus microscopes (among other polarizing models) on my Geological Microscopes website. My particular interest is in petrographic polarizing microscopes, and so some extra attention is paid to Olympus pol versions on this page.
Some History
Olympus developed the BH2 from their BH series of the 1970s. The company also built a similar but slightly smaller, simpler, and less expensive line called the CH (later CH2), which was designed for the education and clinical markets. The earlier Olympus lines of EH, FH, POM, and other microscopes were nothing like the BH -- it was a completely new design, not a transition. Olympus adopted a modern style of boxy base, riser, and arm for the BH stand, and it is quite large relative to contemporary models by other makers. This allowed interior space for electrical and optical parts, and people like me appreciate the room for large hands around the knobs and controls. A variety of removable modular parts adapt the same stand to different applications -- not a new concept, but an important one. The earlier BH and CH stands had an utilitarian "warm gray" semi-metallic hammered finish, which in my opinion, detracted from the otherwise fine design. The "Olympus beige" color of the BH2/CH2 models is much more successful, and likewise copied by others.
The general form of the BH was preserved in the BH2, and also its 160 mm tube length, head design, focus mechanics, some intermediate tubes, reflecting light accessories, removable nose turret, etc. It is possible to swap some of those parts between the BH and BH2 models, but new lines of eyepieces, objectives, and condensers were developed for the BH2. Its new "long barrel" objectives have 45 mm focal lengths, and new eyepieces provide final corrections of chromatic aberrations with the objectives; you should use them together. The BH2 also had new lighting with halogen lamps. Obviously, a tremendous effort went into the BH, and then more into the BH2, and it was all very well done.
I have read that even after Olympus started to produce the BX series as its replacement in 1993, the BH2 stayed in production to meet demand that continued from happy users. I don't know when that ended, but many BH2 parts are still stocked by dealers. Certainly an ever-growing number of used BH2 microscopes and parts are now available, especially on eBay, at a fraction of new cost -- I say hooray! Somewhat oddly, the BHS-P polarizing model was marketed in the same 1980 catalog that describes gray-body AH-P and CHA-P pol models, with no BH or BH2 pol scopes mentioned. That must have been a transition year. Even more oddly, the POS microscope that was designed in the 1960s as an update of even earlier stands was still available in 1996, according to the biological microscopes brochure posted below. Some historical information about the BH/BH2, CH and BX lines is repeated from the Olympus microscope history webpage:
BH Series (1974)
"With the BH Modular Series, launched in 1974, the microscopes could be transformed to meet various specifications, including polarization, phase contrast, differential interference, and simple transmission fluorescence microscopy. The previous E and F Series of microscope bodies and the POS and POM models were specialized devices with more restricted uses or specifications. The BH Series, however, could be used for a wide variety of observations simply by switching the microscope head or lens modules. The BH Series was also the first Olympus product to feature a coaxial handle attachable to the left of the plane stage, which allowed the stage to be easily moved on a vertical or horizontal axis. Olympus launched the BHA and BHB models for research and test purposes, whereas the BHC model was meant for test and practical study. The BH Series was subsequently developed further into the BH2 and the BX.
CH Series (1976)
"In 1976, Olympus launched the CH Series, a modular biological microscope for practical laboratory teaching applications, in place of the KHS, KHC, HSB, and HSC. The CH Series could meet diverse needs because of its excellent performance and modular design. The Series comprised three models: the CHA (6V 10W halogen light source), CHB (20W tungsten light source), and CHC (the mirror CH-MM or the CH-LSK 20W with a simple illumination device). The Series was painted in a warm gray color. By switching modules, the microscope could be used for simple polarization, drawing, or incident light (metallurgical) microscopy. The CH Series used the same modules as the BH Series. The CH Series was marketed for 10 years, until the release of the CH2 Series.
BH2 Series (1980)
"The BH2, from the high sales volume BH series, debuted in 1980. The company developed the BH2 Series ahead of the AH2 Series, building a microscope that approached the optical performance of overseas products and provided even greater freedom in modular combinations. The objective lens can be described as the heart of a microscope. Until the BH2 Series debut, microscopes tended to have short barrels, with a focal length of 36.65mm and a mechanical tube length of 160mm. Olympus then developed a long barrel (LB) objective lens series (1x–100x oil) with a focal length of 45mm and a mechanical tube length of 160mm that could be used for everything from regular bright field observations to polarization, fluorescence, and phase contrast microscopy. As a result, the BH2 Series captured the highest share of the global market. The company's main microscopy revenue stream was therefore on more solid ground. In 1981, Olympus developed the IC Series featuring an LB objective lens for industrial applications and the universal vertical illuminator UMA for additional industrial applications. The company then developed further improved models for the BX and CX Series, utilizing a UIS objective lens.
BX Series (1993)
"The BX Series (BX40, BX50, BX60), launched in 1993, used a novel Y-shaped design for the microscope body. The series featured superior operability, excellent rigidity, and first-class optical performance. A wide range of accessories was also available to expand the range of observations possible. Olympus succeeded in providing the optimal viewing environment for all observations. At the same time as developing the UIS objective lens, Olympus worked on designing a Y-shaped microscope body in a bid to further evolve the AH2, BH2, and CH2 Series and
establish a global leadership position. There was heated debate amongst the developers from the concept generation stage, but unstinting efforts and expertise by the development and manufacturing divisions resulted in the debut of this product with the tagline "Yes is the answer." YES is an acronym for Y-shaped ergonomics, Excellent optics, System versatility. This product range took the competition by surprise and was extremely well received by microscope users."
Olympus now makes their CX line of microscopes in the Philippines, and some components for other models are made there and also imported from China. Otherwise, Olympus maintains a heritage of very fine Japanese microscope designs, construction, and superior optical quality. The BX line has already progressed through the BX2 and now (late 2011) the BX3, which to my eyes looks like something designed for the Star Wars movies. Interestingly, it appears that parts for polarizing models have continued essentially unchanged from the initial BX models. Recently there have been more parts and whole microscopes of the BX series on eBay, so as time goes by I will add these to my webpage. I now have a BX-50 polarizing microscope to restore and possibly use for research (also a collection of BX documents), and I will see if it actually improves on my extremely fine BH2 BHSP.
Renovating and Equipping the BH2
In general, BH2 stands are durable and easy to work on, and if they have seen normal use and maintenance, you can usually assume a used one can be cleaned up to give you many more years of reliable service. If you need some parts, you can generally buy another used BH2 with what you need, and cherry pick the best pieces to make one good microscope out of your two not-so-good scopes. Then clean up and resell what you don't need on eBay. A few BH2 and CH2 stands have come my way with electrical faults and bad coarse focusing gears, but such problems appear to be rare. I am amazed by the amount of dirt that often arrives on used microscopes, not to mention the stupid stickers, tape, and magic marker labels. But with patience and the right cleaning agents, a quality microscope can be made very nice, if not like new. Chips and scrapes in the enamel paint of the the stand are also common. Not having found an exact match of any commercial paint for the Olympus Beige, I mix a close match using little jars of Testor brand model enamel paint, which requires white with a bit of brown and yellow, and maybe a few other colors. The beige color of Olympus BH2 and CH2 stands is not always exactly uniform among examples I have owned.
You can probably find a decent working BHT version on eBay for around $1100 to $1400 or so, complete with four DPlan objectives and perhaps even a trinocular head (worth at least $200 more than the binocular head). The BHTU version is less valuable by $200 or more, although it was supposedly available because of higher demand for the tilt-inward design of the turret. The swing-up top lens BH2-SC condenser goes for about triple the price of a standard Abbe, and even more is asked for the Aplanatic (AAC) condenser. In fact, the standard and common CD Abbe condenser is satisfactory nearly all the time. However, if you want to get good use from low powers such as the 2x and 4x objectives, go for the swing-top SC version, as the low n.a. with the top lens down helps to illuminate the whole view. There was also a special condenser called the BH2-ULC to use with 1x and 2x objectives. For high power viewing the Aplanat can't be beat, but match it with SPlan or Apo objectives if you can afford them.
"D Achromat" (labelled "A") and DPlan objectives, and both WHK and WK eyepiece versions are reasonably abundant and relatively affordable, and they are excellent. SPlan objectives can be half again to twice as expensive as DPlans, and the Apochromat optic lines are still sky high (but no doubt worth it). Versions of plain achromat and D Plan objectives with a special PO label on them are certified strain-free for polarizing techniques, and they are even more expensive then the SPlans (which are not available with PO labels). However, my colleagues and I find that "normal" biological A, DPlan and SPlan Olympus objectives show little to no obvious strain effects, so go ahead and use them with polarizing filters (the SPlans also have higher resolution and wider plan focus than the DPlan PO versions). Phase contrast objectives should be good too, but probably the Apochromat objectives are problematic for polarizing use due to all those interior lens layers, although having never owned any, I don't know this personally.
The DPlan objectives work great with standard wide-view 10x eyepieces such as the WHK and WK models, which have an excellent field number of 20. But if you are lucky enough to have one of the rather rare super-wide heads with their 30 mm diameter FN 26.5 SWHK eyepieces, the SPlan objective line is designed to provide flat focus across that extreme view field. You also might wish to use them with the swing-up SC condenser.
Some folks mix and match Olympus BH2 optics with parts made by Nikon for their Labophot/Optiphot and later 160 mm mechanical tube length models. They have generally similar performance parameters, but of course Olympus and Nikon will tell you how their objectives and eyepieces are made to work together for the best corrections of color aberrations and planar focus. I'm sure it's true, but whether you will notice or care much is up to you. The condensers for the two makers appear to fit each other's stands, and surprisingly, so do their removable stages. On eBay you will find many more parts and accessories for the BH-2 than for Labophots and Optiphots, no doubt a reflection of sales volumes. I try to stick with parts original to my microscope models, although it is not always easy.
As far as my "new" BX50 polarizing microscope (late 1990s), I find it has really excellent optics and a great big conoscopic image, but I am concerned about all the electronic components and their potential for expensive failure. And parts are expensive! The surface-mount electrical parts of the BH2 can be serviced or else if necessary, it is easy and relatively cheap to buy another stand for parts, and to swap out the light-source base.
Photos, Links, and Docs
In the sections below are images of various BH/BH2/CH/CH2 microscopes and parts that I have owned, and kept or sold over the years. There are also versions that I have not yet seen, and if you have other images or documents to share please share them: I am happy to acknowledge your generosity. In addition, there are pdf files of sales brochures, catalogs, and instruction manuals that I own or have borrowed, including some for other Olympus models. These are for your personal information only, not for sale or commercial use including eBay. Several photos from this page have been taken recently and used on eBay -- a fraud, as they do not show the item actually for sale. If you see someone stealing a photo for their profit, please let me know.
Click on the image thumbnail for a larger version, on a web link, or on the document name to download a pdf (warning: it may be a large file). I enjoy hearing from folks who use these microscopes, and if you have some suggestions or contributions for this web page, please contact me.
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Images in jpeg Format copyright J. G. McHone 2009 all rights reserved
The BHA had a more powerful bulb in an attached lamp house. plus a built-in output and switch for a second lamp in the incident light tube. It also had an internal swing-up lens to be used with higher power viewing.
The high 1.4 n.a. aplanatic condenser for the BHA used built-in centering bolts, as the ring holder for it had none.
The BHC model had a somewhat less powerful 15 watt lamp in a holder assembly like the one used for the BHA, plugged directly into the back of the base.
Older-style short barrel (37 mm) objectives were carried over from earlier models, and used in both the BH and CH lines. Their optical quality is very good.
For dedicated reflected light work, the BHM used a simplified base without transmitted light capabilities, and an external transformer.
The CHA-P or polarizing version had the same pol accessories as the BHA-P with some modifications to fit the smaller frame, and it had to be ordered from the factory. Its halogen lamp is only 10 watts but appears brighter than the 30 watt tungsten bulb.
The CH-BS was marketed for education. The CH line started in the "warm gray" finish like the BH stands, but before the CH2 model was in production, CH stands adopted the beige finish as used on the BH2.
A nifty clam-shell style hard plastic case was available for storing and carrying the CH microscopes. There was also a larger hard case for the BH2, but the older BH series still used old fashioned wooden cases.
D Achromat objectives, a somewhat more economical line of "long barrel" or 45 mm focal distance objectives developed with the BH2. Also used in the CH2.
SPlan objectives have shinier barrels than most of the DPlan line. Also higher numerical apertures (except for the 100x), and they can maintain planar focus up to 26.5 FN.
MSPlan (metallurgical) objectives also fit the standard 20.3 mm turret holes. There is also a MDPlan line. Incident light passes down through them to the sample but they also work fine for transmitted light. Note the nice high n.a. values.
The Plan Water immersion objectives must have been very rare, as I have never seen them in any catalogs. This 4x would be useful for watching little creatures swimming in a drop of water.
The very rare tilt-tube head is large enough to look a little awkward on a normal BHT stand, but it is really nice to adjust the viewing to a comfortable angle. This one has an "MTV3" accessory tube attachment.
The BH2-SC condenser with a swing-up top lens allows easy change between n.a. 0.16 and n.a. 0.9, very helpful for fully illuminating low power views. Beneath it is a tube-type polarizing filter that fits over the field lens.
The BH2-AAC aplanatic condenser uses 7 elements for its 1.4 n.a., a good match for high-n.a. SPlan and Apo objectives. The rings beneath it can hold 3 filters that swing on a pivot.
BH2-PA intermediate tube for petrographic microscopy, with a rotating graduated analyzer, focusable Bertrand lens, and a slot for a 6x20 mm compensating wave plate. The 4-place nosepiece BH-PRE includes 3 centering places, which use a special wrench or small screwdriver.
BH2 BHS for biological bright field applications, with TR-30 trinocular head, a right-hand SVR stage, and SPlan brightfield objectives. The SPlan objectives have enhanced numerical apertures and planar views up to the FN 26.5 of the super-wide head and SWHK oculars.
(more images will be added as I dig them out of my files) |
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Documents in pdf format
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