After working and playing with more than 60 different microscope makes and models for research, teaching, and pleasure, my favorites are the various versions of the Olympus BH-2. It is not that they have features much better than the best features of other microscopes; it is just that they are so good in all their functions. Plus I think they are very good looking! Proof is that other makers have copied the general design and styling of the BH-2 and its smaller sibling the CH-2, for several decades now. But, none match the combination of good engineering, high quality, fine optics, durability, and smooth operation that characterize the various BH-2 models. Olympus sold a huge number in the 1980s and 1990s; many are still in service, and parts remain abundant. In my hobby of renovating microscopes, I enjoy collecting and working on all brands and types that are polarizing, and also on the various Olympus BH-2 and associated 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!
BH-2 microscopes are relatively easy to service, and their high quality means they can stay in great condition even after years of use. Photos of my Olympus microscopes and their parts, and my collection of documents and web links about Olympus BH-2, CH-2 and related models, are shared on this page. Also see my wonderful BH-2 BHSP and other descriptions of Olympus microscopes (among other polarizing models) on my Geological Microscopes website.
Olympus developed the BH-2 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 CH-2), 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 "battleship grey" semi-metallic hammered finish, which in my opinion, detracted from the otherwise fine design. The "Olympus beige" color of the BH-2/CH-2 models is much more successful, and likewise copied by others.
The general form of the BH was preserved in the BH-2, 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 BH-2 models, but new lines of eyepieces, objectives, and condensers were developed for the BH-2. 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 BH-2 also had new lighting with halogen lamps. Obviously, a tremendous effort went into the BH, and then more into the BH-2, and it was all very well done.
Even after Olympus started to produce the BX series as its replacement in 1993, the BH-2 stayed in production to meet demand that continued from happy users. I don't know when that ended, but I am told that many BH-2 parts are still stocked by dealers. Certainly an ever-growing number of used BH-2 microscopes and parts are now available, especially on eBay, at a fraction of new cost -- I say hooray! Some historical information about the BH/BH2-CH/CH2 lines is repeated below from the Olympus 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."
In the sections below are images of various BH/BH-2/CH/CH-2 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 send 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. I don't own the document copyrights, but files scanned from documents in my library are my property. 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 reflected light tube.
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 lamp in a snug fitting.
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 CH-BS was marketed for education. The CH line started in the "warm gray" finish like the BH stands, but before the CH-2 model was in production, CH stands adopted the beige finish as used on the BH-2.
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 BH-2, 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 BH-2. Also used in the CH-2.
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.
BH-2 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.
MSPlan objectives also fit the standard 20.3 mm turret holes. There is also a MDPlan line. M stands for metallurgical, and the incident light passes down through them to the sample.
(more images will be added as I dig them out of old files) |
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Documents in pdf format
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