MicrobeHunter.com Microscopy Forum

Hi all,

I have recently acquired an Olympus BH2, with a rather odd mix of objectives:

• Zeiss Plan 2.5x/0.08
• Olympus SPlan 10x 0.30
• Zeiss Neofluar 40x 0.75
• Zeiss A-Plan 100/1.25 oil (I don't think I have any intention of using this.. we never use 100x at work)

I currently have Nikon HKW 10x eyepieces, is there any advantage to switching to olympus WK or WHK objectives? What is the difference between WK and WHK anyway?

I will probably look out for Olympus D-Plan or S-Plan objectives (20x an 4x) and to replace the Zeiss 40x (which incidentally works ok, but isn't great towards the edge of the field). The Zeiss 2.5x actually works very well.


Random background: I work as a pathologist (currently a trainee), so I spend most of my day at work using a microscope anyway. In spite of this, I (and most pathologists, I believe) know rather little about microscopes!

Many thanks!

Olympus WK and WHK eyepieces provide compensation for residual chromatic aberration (color fringing) of the Olympus LB objectives. Without these eyepieces, LB objectives will create noticeable lateral chromatic aberration. These eyepieces are a poor match for Nikon and Zeiss optics. You should go with a single manufacterers objectives, and use them with the proper eyepieces.

Carl

Whk have a higher eyepoint than wk, otherwise they're the same. Selling the zeiss objectives could certainly help fund your quest, since they tend to sell well and it's a pricey brand. Low mag objectives are pricier and rarer so if it works well you might want to keep the 2.5x though.
Some mismatching of eyepieces and objectives will yield ok results (particularly for visual usage) but will be more obvious in photography. I recently tried a leitz stand with a leitz, a wild, a zeiss and a nikon on it, and only the nikon looked particularly bad to the eye through the leitz eyepieces. But you lose parfocality that way too and it's just not as good. That scope was in a lab and cobbled together from parts, so I am not sure how often it was used with that configuration if ever.

Many thanks for your responses!

I will probably switch to olympus eyepieces in that case, if they are corrected for olympus objectives. Olympus SPlans are not too cheap though!
I haven't noticed chromatic aberration so far (I've only noticed what I think is a lack of field flatness with the Neofluar 40x), but i'll look for it when I come across something particularly contrasty.

Thanks again

You might be very pleased with Olympus DPlan objectives. The SPlan has a wider field of view (up to FN26); which unless you have a widefield head and eyepieces you won't take advantage of. They also have a slightly higher numerical aperture, somewhat like a plan fluorite objective, which gives slightly better resolution and, likely, correction. Finally, they might be a bit more likely to be strain free since Olympus recommended them for DIC.

All that said, the DPlan objectives are excellent, more affordable, and often good (strain free) for polarization and DIC without being so marked. If you don't plan on buying a widefield head and eyepieces, they'd still give excellent images and likely be significantly less costly. Your 10x SPlan would still be at home on a nosepiece with DPlan 20x and 40x.

The Nikon HKW eyepieces are likely a poor choice, since they're correcting eyepieces with no older Nikons on the turret to be corrected. As Carl and others have said, and you've concluded, once you go all Olympus, the WK or WHK 10x/20 will be the way to go.

PeteM's right about the DPlans. I used them in hematology and microbiology in a trauma center lab for a long time. They're nice lenses and relatively inexpensive. Get the WHK eyepieces. Their higher eye point is easier to use over a long period of time.

Tom

The incompatibility between Zeiss objectives and Olympus eyepieces (or vice versa) is more prominent in camera images than in direct eye vision.
About your Zeiss objectives: an A-plan objective might be a fairly modern infinity corrected objective. Quite expensive lens. Check whether your 100X1.25 is marked with an infinity sign or alternatively 160. The other ones, 2.5x0.08 and Neofluar 40X0.75, belong to a much older generation, 160mm tube length microscopes. 160mm TL objectives are less costly than infinity-corrected, and I would verify that they are not delaminated.