Olympus BH-2 objectives

[Mycogirl]

I'm a novice looking for my first microscope, mainly for mycology, and thanks to advice and research on here and elsewhere have pretty much decided to aim for a nice used/refurbished Olympus BH-2. They seem to come up fairly regularly on eBay and I'm slowly getting some sense of the prices they go for, which vary quite a lot. One thing I can't quite work out though is how relevant it is to have genuine Olympus objectives, as quite a few of the advertised scopes seem to have apparently unbranded objectives, or at least the manufacturer is not visible in the listings photographs. Is there a big difference in the results one could expect to get from Olympus vs other objectives, and should this be something that significantly affects the price of a BH-2? Thanks very much for any thoughts or advice!

[perrywespa]

From what I've learned on this forum, many manufacturers' microscopes, Olympus included, are designed so the eyepieces correct some of the optical qualities of their objectives, such as spherical and chromatic abberation. Therefore, the scopes perform best when eyepiece and objective are from the same manufacturer. Having said that, I have generic 20X and 60X objectives on my Olympus CH-2 and they do well for me. The Oly versions were just too expensive. It ultimately depends on how critical one is and one's budget. Hope this helps and welcome to this wonder place!

[AntoniScott]

To Mycogirl:
The Olympus BH2 is an excellent choice compared to the endless variety of crap-shoot alternatives with objectives of unknown optical quality.
There is another less expensive Olympus choice that you moght consider, the CH2. I was very fortunate to have purchased a CH2, probably 15 years old, that was never used and was in the original container. The CH2 was considered a student-type model and was equiped with E series objectives. I did an exhaustive side by side comparison between the E series and other more epensive Olympus objectives and was hard pressed to see any difference.

The BH2 is avialable with four or five objective turrets ( six objectives if you find the right BH2 frame), the CH2 with only a four objective turret. The BH2 does not allow dark-field observation without a third party accessory attached, the CH2 does allow dark-field observation. Both are available with Trinocular heads to allow a camera to be attached. The trinocular and binocular heads are interchangeable betweem the CH2 and the BH2.

The lighting in the CH2 is accomplished with a bulb built into the frame and gives a superb overall lighting to the specimin. The BH2 has a bulb attached to the rear of the frame and does not give as good an overall lighting as does the CH2 ( important to me). Some earlier BH2 frames allowed the removal of the objective turret head from the frame ( a very nice feature).

Since my interest is entomology and I prepare many whole mount insect slides, I rarely need anything more that a 20x objective. Even then, I use a specialty 20x that has a longer working distance that the higher quailty Olympus 20x objective. T


I use both the BH2 and the CH2 equaally as much. My BH2 has removable five and six objective turret heads , my CH2 has a fixed four objective turret head.

[Mycogirl]

Thank you very much, Perry and Antoni. It is very interesting to hear your experiences. I re-read a document from Carl Hunsinger in the US and realised that he says exactly what you say, Perry, about the Olympus objectives and eyepieces being mutually correcting so that in theory at least one gets the best results from using the two together (or using Nikon objectives and uncorrected eyepieces), but it sounds as if there are third-party objectives that have similar correction to the Olympus ones, which may explain why you get such good results. It gives me hope that if I want to try phase contrast in the future and can't afford Olympus objectives there might still be a good alternative - many thanks for sharing your experience!

And thank you both for the heads-up about the CH scopes. I was not aware of those but they sound rather good and I will look into that as an option.

I'm so grateful for all the generous sharing of knowledge on here! Such a brilliant forum.

[PeteM]

You can use good quality finite objectives that aren't Olympus (such as the better imports) as long as you use the corresponding eyepieces. It's not so easy to mix others' phase contrast objectives, unless you also fit their phase condenser.

The BH2 is a fine microscope -- and well documented by Carl and others -- but there are others equally good, and sometimes offered at lower prices. If you really want phase contrast, Olympus BH2 prices in particular have risen rapidly.

I personally think it's worthwhile to get a scope with five rather than four spaces for objectives, a minimum of a 20 watt halogen lamp, and the somewhat wider field of view of 20mm (versus the fixed four hole nosepieces, dimmer lamps, and 18mm field on some of the educational Olympus and other makers' models). An extra $100 spent now won't seem like much over the years.

[deBult]

I have both BH2 and CH2 scopes.

The Olympus CH2 serie has 20 Watt halogen or 30 Watt filament illumination, the 20 Watt has enough power for all bright field and phase options except 100* phase contrast (it is relatively simple to add a LED option if you insist: main reason to do this is constant color temperature when taking pictures and heat reduction, useful for observation of protozoa and pond samples: they don’t appreciate heat).

A CH2 is fitted standard with 18 mm field of view eyepieces, but-can be retro fitted later with the BH2 WHK 20 mm field eyepieces.

The CH2 phase set has 10* and 40* phase annuli plus a very useful dark field setting, it is “plastic” not metal, but often way cheaper compared to the BH2 phase condenser (the BH2 phase condenser is compatible with the CH2, the CH2 phase condenser does not match the BH2).

All Olympus LB (Long Barrel) objectives are interchangeable and can be used on both CH2 and BH2.

Do not mix and match the older Olympus Short Barrel (37 mm) objectives and or eyepieces with the Long Barrel (45 mm) series, the original BH / CH phase condenser it is not compatible with LB phase objectives.

Replacing the CH2 4-tuple revolving nosepiece with a BH2 quintuple requires a fitting JIS-type screwdriver only (I still have to try this one though).

[AntoniScott]

After reading posts from other members of this forum, I would like to add a few more comments. Correct me if I am wrong, but Mycogirl suggested that she was new to this microscope choice which can be daunting if you are not aware of the myriad of choices out there. Simplifying the choices I would think would be most helpful at this time, so staying with an Olympus BH2 or CH2 would be the best advice I would give. As well as fine optical instruments, there is a huge variety of used equipment available.


One member suggested that there are other brand good optical quality import choices available, and I cannot disagree with that statement, but figuring out which no-brand objectives are better and others not so good is a problem. It's better to stick with a brand name that you know that has a good reputation for optical quality. It is acceptable to use brand names such as Nikon along with Olympus as long as the barrel length of the microscope is the same ( i.e. 160mm). However, ther are so many Olympus objectives on the used market that are available, there is no reason to mix and match.

The real issue with buying used objectives is to know their condition. The exposed objective lens glass can be damaged through misuse. 20x, 40x, 60x objectives can be damaged by immersing in the medium to be viewed and improperly cleaned, etc. Never buy anything that can't be returned.

Finally, the choice of the frame ( CH2 vs BH2) is the least important choice. The BH2 usually is supplied with wider field eyepieces ( 18mm, 20mm 22mm) which is a preferred feature but by no means makes the CH2 eyepieces a bad choice. These wide field eyepieces fit the CH2. Also BH2 and CH2 binocular heads are interchangeable.

The nice thing is that upgrading from one eyepiece to another, switching bonocular heads or replacing objectives is all possible via the used micrsoscope market.

[dtsh]

After reading posts from other members of this forum, I would like to add a few more comments. Correct me if I am wrong, but Mycogirl suggested that she was new to this microscope choice which can be daunting if you are not aware of the myriad of choices out there. Simplifying the choices I would think would be most helpful at this time, so staying with an Olympus BH2 or CH2 would be the best advice I would give. As well as fine optical instruments, there is a huge variety of used equipment available.


One member suggested that there are other brand good optical quality import choices available, and I cannot disagree with that statement, but figuring out which no-brand objectives are better and others not so good is a problem. It's better to stick with a brand name that you know that has a good reputation for optical quality. It is acceptable to use brand names such as Nikon along with Olympus as long as the barrel length of the microscope is the same ( i.e. 160mm). However, ther are so many Olympus objectives on the used market that are available, there is no reason to mix and match.

The real issue with buying used objectives is to know their condition. The exposed objective lens glass can be damaged through misuse. 20x, 40x, 60x objectives can be damaged by immersing in the medium to be viewed and improperly cleaned, etc. Never buy anything that can't be returned.

Finally, the choice of the frame ( CH2 vs BH2) is the least important choice. The BH2 usually is supplied with wider field eyepieces ( 18mm, 20mm 22mm) which is a preferred feature but by no means makes the CH2 eyepieces a bad choice. These wide field eyepieces fit the CH2. Also BH2 and CH2 binocular heads are interchangeable.

The nice thing is that upgrading from one eyepiece to another, switching bonocular heads or replacing objectives is all possible via the used micrsoscope market.

Another possibility if in North America are the AO infinity scopes. There are tons of accessories available and often quite inexpensively. $200-$300 will often get a person an instrument with 4x, 10x, 40x, and 100x plan achromat objectives, trinocular head, and a mechanical stage. The Series 10 and 110 are common and good instruments, but the 150 (student scope) can sometimes be found for absurdly low prices. The 150 aren't as nice as the 10 and 110, but they share the same optical design and careful looking can often get a functional instrument for around $100 including shipping.

An arguable disadvantage of the AO infinity scopes are that you're limited to AO's somewhat small selection of very nice objectives. Not at all knocking the BH2/CH2 series, fine instruments and more upgradable, but also typically cost more.

[AntoniScott]

Although I am a genuine microscopist and enjoy using microscopes of all kinds, my obsession is also as a collector of many of these optical precision instruments. The history of the microscope fascinates me. I'm awed at the high level of optical excellence and precision in microscopes of decades ago back to the early 1900's and into the 1800's.

A recent aquisition was a microscope ( probably available in the 1970's) made by Bristoline that had short barrel objectives. I would have never expected a microscope with a name like Brisoline to have such high quality optics. The optical quality was impressive. I was able to find extra short barrel objectives made by Bausch and Lomb, Spencer and A/O that all had outstanding optical quality, to add to my collection.

Having so many microscopes and objectives at hand , both short and long, gave me a unique opportuniy to perform A-B comparisons of similar focal length objectives, side by side on the same turret( i.e. 40x) and similar brands. Since everything I own is used, not new (except the Olympus CH2), I was able to accumulate a collection of the best optical quality objectives that I placed on one objective turret that I use for the most critical observation or photography. The lesser quality objectives are used for most of my entomolgy work.

One of my BH2 Olympus microscopes is an early BHT model which has the ability to remove the objective turrent in a few seconds. Additional turrents available with four, five and six objectives are available and can be installed in a few seconds. Very nice feature.

[Mycogirl]

Gosh, thank you so much everyone! I am indeed a total beginner in this strange but also fascinating and new (to me) world of microscopes. You've all given me a huge amount to think about - and just when I thought I was homing in on a decision! I am starting to see why people end up owning shelves of these instruments - not that this is an option for me but I can understand how it might happen .

It's going to take me a while to digest all the advice but I'll let you all know what I do in the end. I do really like the idea of the BH-2 mainly I think because of the amazing documentation from Carl Hunsinger and Alan Wood, which have helped me so much to start to understand how these scopes work and what the issues are in buying bits for them. I must admit that the idea of buying secondhand objectives from unknown eBay sources was worrying me a lot and the advice to only buy returnable items is very much taken to heart.

[deBult]

Mycogirl: you have a PM.