Repairing an Olympus 40x Apochromat

[MicroMan2]

Hello, I've recently gotten a lot of objectives featuring a 40x S Plan Apo, however it seems that the previous owner misused objective and caused misalignment of the lens elements making images impossible to make. My question, is it possible to realign the lens elements of the objective or this the endeavor a sunken ship?

[PeteM]

I'd think misalignment would be rare, unless there are signs the objective has been opened up. Is it just the front element that looks pushed in? Are there signs of attempted entry from the back?

Problems like oil intrusion or fungus might be at fault. If you use a phase telescope you may be able to see if any (and which) lens elements might be at fault. I've had some luck repairing this sort of problem, by very careful disassembly -- noting the exact placement and orientation of every lens element, shim, and spacer on the way in. Clean the offending surfaces and you might be rewarded with a decent view upon reassembly. You'll need proper spanners and other tools to accomplish the task.

Olympus' own service is another option; though likely at a cost about the same as buying a good performing objective used.

[MicroMan2]

It seems that the front lens was crashed causing the lens to have become crooked. When I look through the rear focal plane of the objective, the usual circular image of the lens is instead an elliptical. Another observation is that the rear lens washer was easily removed by my hand indicating prior assess to the lens.

[PeteM]

I've never taken an Olympus 40x SPlanApo apart. Is yours the dry one with a correction collar or the oil immersion version?

Most objectives I have disassembled are packed solid with glass and spacers so there really isn't space for an element to go very far cockeyed. The one 40x SPlanPlanApo I have (dry) has a sort of black surround that might possibly get pushed in - don't know. That someone else has likely already been into the objective isn't a good sign. A correction collar will complicate things.

Given that it doesn't work now, you might go in and look around. It won't be a task for the faint hearted. Could be another cheap and damaged objective of the exact same type might provide a clue, maybe some parts if you really enjoy puzzling through this sort of thing.

Better yet, maybe you'll hear from someone who has actually taken one of these apart? Good pictures of the damaged end are likely to help.

[deBult]

Carl Hunsingers guide to freeing up to spring tip on Olympus objectives gives guidance on opening them:

http://alanwood.net/downloads/olympus-l ... ky-tip.pdf


The LB objectives parts diagrams:

http://alanwood.net/downloads/olympus-l ... agrams.pdf

[MicroMan2]

In extension to this thread, as I don't have want to make more threads. I have gotten a S Plan 20 Apo alongside with my 40x. Upon looking through the back of the objective, everything seems fine.
However with usage under the microscope there are some problems. Primarily when looking through a calibration slide using a dot, the formation of image is asymmetrical as I focus above and below the image. There seems to be a slight image plane difference that is unusual for the NA of the objective. I compared this with my S Plan Achromat 40 and it forms an image on a singular plane that the Apo does not. Focusing above and below the image is also symmetrical. Secondly, when trying with oblique lighting, the image formed is absolutely poor and everything becomes blurred rather than a distinct 3d image with a shadow like with my normal SPlan 20x achromat.

Does anybody have a clue on what causes these problems. If one has experienced these problems and they have disassembled their objectives, has the disassembly fixed the issue?

[BramHuntingNematodes]

Not sure exactly but just as a reminder make sure to exhaust all other avenues of inquiry before taking apart objectives.

[houstontx]

I also have a 40x Splan APO with terrible performance, non flat image, hazy and awful spherical abberation. It looks ok through back element, but its not useable on the scope. Also thinking about some kind of disassembly and fix, however improbable.

[fero]

Hello all,
I just got SPlan APO 10x (not sure which version, apparently there are two) which has comma aberration, not possible to focus and hwen refocusing image deforms greatly. I think there must be something loosen inside or missaligned, though I can not imagine how it could happen. May be tightening screw got loosen during transportation. Did some of you trid to open your APOs already?
Thanks,
Fero

[josmann]

I also have a 40x Splan APO with terrible performance, non flat image, hazy and awful spherical abberation. It looks ok through back element, but its not useable on the scope. Also thinking about some kind of disassembly and fix, however improbable.

Just to make sure we're ticking all the boxes - The 40x SPlanApo is absolutely a difficult objective to use and will present a bad image when doing casual microbe hunting. The correction collar must be utilized to get anything close to a sharp image and performance will degrade quickly far beyond the bottom of the coverslip. I wasn't sure mine was good until I looked at my diatom test slide which has the frustules mounted immediately below a precision .17mm coverglass.