How to check BHC-F before buying?

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len
Posts: 66
Joined: Sat Dec 26, 2009 5:51 am

How to check BHC-F before buying?

Post by len »

Hi,
I have a simple am-scope and was thinking about purchasing a trinocular. I saw an Olympus BHC-F ad from a medical clinic for 250$. The lady on the phone doesn't understand too much about it but she said it is in working condition and was used until recently. She doesn't know if the photo tube was ever in use and the microscope come as is.

Do you have any advice on how to check the microscope before buying to verify it is in good condition? I was thinking about looking though the eyepiece but I don't know if anything else could go wrong with the photo tube?

PeteM
Posts: 177
Joined: Sat Jan 05, 2019 12:06 am
Location: West Coast, USA

Re: How to check BHC-F before buying?

Post by PeteM »

The BHC is a decent scope, but i'd be inclined to spend a bit more and consider the next generation Olympus BH2 or Nikon Optiphot scopes. $250 would be a good price for a BHC if equipped with Olympus plan "long barrel" objectives, but a pretty routine find for one with "short barrel" objectives. You might find a newer BH2 version for $100 or so more, depending upon your location.

The focus systems on either the BH or BH2 era scopes are similar and pretty robust. If they seem to move smoothly, they're likely OK.

However, the BH era scopes have heads with an 18mm field of view and depending up the age possibly those "short barrel" objectives.

The BH2 era scopes have heads with a 20mm field of view and "long barrel" objectives.

In addition the BH2 era scopes will start with a brighter illumination system and also be a bit easier to adapt to either flash or LED illumination should you wish still more light. A member here (Saul) makes intelligently designed modules to add LED for focusing and flash for illumination.

Most common problem in my experience is with the power supplies and general condition (dirt, dried grease, misuse). Easy enough to check. Make sure the lamps turn on and adjust through their range. Make sure everything moves and be prepared to thoroughly clean and lube the scope. Carl Hunsinger, who I believe occasionally posts here, has produced wonderful guides to maintaining the BH2 series scopes.

Depending upon how you intend to use the scope, having the option of interchangeable nosepieces can be handy. That would put you into an Olympus BHT or BHS (BH2 generation) or a Nikon Optiphot (1) or 2. For the Optiphot the most common failure mode is the fine focus gear -- not too difficult or costly a repair thanks to a replacement gear made available by a member (Lothman) here.

Nikon scopes of this era are also "chrome free" which means you don't need compensating eyepieces or relay lenses to get a relatively aberration-free image into your camera. This is sometimes handy to match what you see through the eyepieces to the view seen by the sensor of your camera. A Nikon would likely be easier to adapt to sensor sizes smaller than full frame (APS-C, 1" Sony, etc.).

However, if you plan to use a full frame camera, the commonly available Olympus 2.5x photo relay lenses meant for film cameras will work pretty well. Otherwise, you may choose to go "afocal" and pick up your image through an eyepiece and a camera lens.

len
Posts: 66
Joined: Sat Dec 26, 2009 5:51 am

Re: How to check BHC-F before buying?

Post by len »

PeteM wrote:
Mon Nov 08, 2021 9:00 pm
The BHC is a decent scope, but i'd be inclined to spend a bit more and consider the next generation Olympus BH2 or Nikon Optiphot scopes. $250 would be a good price for a BHC if equipped with Olympus plan "long barrel" objectives, but a pretty routine find for one with "short barrel" objectives. You might find a newer BH2 version for $100 or so more, depending upon your location.
I'm not sure how to identify SB and LB. they send some photos, see below. If those are "short barrel" does it mean I can't use a modern objective with it? For example use the objectives from my am-scope?
PeteM wrote:
Mon Nov 08, 2021 9:00 pm
However, if you plan to use a full frame camera, the commonly available Olympus 2.5x photo relay lenses meant for film cameras will work pretty well. Otherwise, you may choose to go "afocal" and pick up your image through an eyepiece and a camera lens.
Isn't it possible to attach a crop sensor camera directlly to the photo tube without a 2.5X lens? Isn't it the same as using a camera with a 160mm empty tube?
Attachments
plan 20.jpeg
hi 100.jpeg
pl20.jpeg

viktor j nilsson
Posts: 423
Joined: Fri Mar 01, 2013 1:43 am
Location: Lund, Sweden

Re: How to check BHC-F before buying?

Post by viktor j nilsson »

Those are the Olympus short barrel plan achromats. 36.65mm parfocal. Pickup point 16mm down the tube. The SB plan achromats are kind of meh. The SB plan apos and fluorites are pretty nice and can often be found pretty cheap. Not as good as Olympus LB SPlanApos and Nikon CF plan apos, but pretty good anyway.

You can use any 160mm objectives on a BH. But you will want to use an eyepiece in the trinocular tube that match the objectives. The Olympus FK 2.5x photo eyepiece is the one designed for the Olympus SB objectives.

Pau
Site Admin
Posts: 6051
Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Re: How to check BHC-F before buying?

Post by Pau »

If the seller has no minimum knowledge for setting up a microscope, the only good way I know is to buy with return privilege: this way you will be the tester.
viktor j nilsson wrote:
Tue Nov 09, 2021 8:51 am
Those are the Olympus short barrel plan achromats. 36.65mm parfocal. Pickup point 16mm down the tube. The SB plan achromats are kind of meh. The SB plan apos and fluorites are pretty nice and can often be found pretty cheap. Not as good as Olympus LB SPlanApos and Nikon CF plan apos, but pretty good anyway.

You can use any 160mm objectives on a BH. But you will want to use an eyepiece in the trinocular tube that match the objectives. The Olympus FK 2.5x photo eyepiece is the one designed for the Olympus SB objectives.
Some points:
1- I would advise against mixing short barrel and long barrel (DIN) objectives as this is the recipe of the disaster damaging slides and even the objectives when changing magnification.
2- The Olympus BH and CH designed for short barrel objectives don't have a physical stop to prevent DIN objectives colliding with the slide, you can set one with the lever but this doesn't stop the fine focus and also you will easily lose that position (see the manual)
3- Olympus objectives for 160 finite corrected microscopes need the matched compensating eyepieces to correct the lateral chromatic aberration, you need Olympus projective eyepieces or afocal with visual eyepieces and camera lens, no direct projection is advisable excepted if you use Nikon CF objectives (as formerly stated by Pete)
Pau

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