NIKON PlanApo 100X/140 oil that is a PlanApo 60X/140 oil

[stjepo]

Remember that I have these lenses enclosed in the barrel. I will try to get better photos but it is not an easy task. Basically, that's what I see. When I get rid of the humidity that that dew produces on the lens I will send more photos.

Yes, there are "3 reflective surfaces" if the photograph is from the front lens.

[PeteM]

Stjepo, FWIW, the white dot in your photo, if repeated three times around the barrel, is likely the elastomer mentioned earlier. Digging that out may help free the entire front lens assembly.

At this point, rescuing this objective is a testament to your patience and ingenuity. Don Quixote would be impressed - and we are, too.

[stjepo]

View from the rear, lighting from above zoom from bottom to top. Next to come... if my battery get charged

[stjepo]

Stjepo, FWIW, the white dot in your photo, if repeated three times around the barrel, is likely the elastomer mentioned earlier. Digging that out may help free the entire front lens assembly.

At this point, rescuing this objective is a testament to your patience and ingenuity. Don Quixote would be impressed - and we are, too.

I will see I can fix it without "free the entire front lens assembly" if not I will kill the bull!!

Very nice comment, thank you

[apochronaut]

Digging that out may help free the entire front lens assembly.

The front lens cell is assembled from the rear forward by necessity and it is required to be mechanically tight and sealed against the front bezel. You can't "free" lenses from a lens cell without essentially breaking the cell. which then requires considerable expertise and precision to reseal them in the cell and in proper alignment. Since it seems the front lens is already loose, removing it from the front means that the front lens shoulder is hopelessly broken and the front lens can no longer be fitted into it's original secure mount. Removing it from the rear based on the information I'm getting from stjepo means the removal of a 2 other lenses must precede it, each needing the removal of their secure mounting method as well. Once "freed" the lenses could all be cleaned but how then are they be aligned and remounted in the cell?

[stjepo]

Apronaut, it has been impossible for me to obtain images of what I see, so I have made a drawing of them (very far from what the eye can offer). I have been able to determine where the oil accumulated, now invaded by alcohol that little by little can be cleaned.

Thank you for your patience.

Dirt that keeps coming:

DIRT2.jpg (35.44 KiB) Viewed 1759 times

My drawing:

DIBUJO.jpg (46.33 KiB) Viewed 1759 times

My hypothesis about where the oil inlet is:

LEAKING ZONE.jpg (85.56 KiB) Viewed 1759 times

[stjepo]

For the record:

VISTA 2.jpg (62.88 KiB) Viewed 1756 times

[stjepo]

"More wood" (Marx)

[apochronaut]

Is the front lens loose? You made reference to Galileo " yet it moves" or something akin. It sounded like the front lens is loose in it's mount.

Using your objective schematic as a rough guide, the location of the oil you now indicate as being between the front lens cell and the second lens cell. Initially I took it that you thought that it was inside the front cell.
If the oil is between lens cells, you just break the objective down and clean it. The oil has entered through the white gasket that seals the front bezel off in the barrel.
If it is inside the front cell, that is a whole other problem and indicates a leak around the front lens element : between the lens and the bezel or front lens carrier.

Which is it?

[stjepo]

Forgive me Apochronaut for my doubts, remember that I am very new to this and I am trying to convey the status of the objective to you as much as possible:

1. Definitely the Isopropyl Alcohol is behind the front lens, it is deposited in the cone of the objective. To be more sure, I used a hair dryer to heat the front part and several drops immediately came out and then evaporated. It was where the oil that penetrated inside was deposited. There was nothing in the rest of the objective, now it is clean after the baths I gave to it.

2. Yes and sorry the reference to Galileo was just a little joke. "The front lens is loose in its mount". The front lens moves and I can even rotate it and I can see little pieces of a solid, greasy substance coming out from all its edges and which according to you could be the old solidified oil.

3. Yes "If it is inside the front cell, that is a completely different problem and indicates a leak around the front lens element: between the lens and the bezel or front lens holder." The white gasket is gone.

[apochronaut]

Is this schematic you are showing an accurate depiction of your objective?

[stjepo]

Absolutely not, on Google searching for Apo Microscopic obective I found this one from Olympus, the intention was to tell you where the oil/Isopropyl was deposited.

I have no idea how the lenses are arranged in that last part of this objective, since I don't want to take it apart it is impossible for me to give you an exact description of it.

Now everything looks very clean and is time to assemble it but I won't be able to use the oil to test it as I don't know the lens can be sealed against the metal.

In that moment I need your wise advice again.

[apochronaut]

Modern objectives are assembled in a stacked column of physically sealed lens cells with seams between them. When an objective is taken apart, the cells can be separated from one another but the lenses within each cell cannot be without special tools and techniques.

Your schematic ( of an Olympus objective) points to the oil invasion as being between cell 1 and 2., between the back convex surface of the front lens and the front concave surface of the meniscus lens in cell 2. Oil in that area can easily be cleaned by separating the 2 cells. It would get in there through the large white seal that surrounds the front lens housing or bezel, or around the front lens.

Your ongoing description however, indicates that the front cell of your objective is different than the schematic you posted. In the schematic, the front lens is a simple plano/convex lens as is the case with many objectives. The next lens is normally a meniscus lens and is the first lens in the second cell .
Based on your description however , it sounds like your front cell is a compound lens cell, not a simple cell as in the picture. It sounds like your front cell contains the meniscus lens as well, so that there is an air space inside your front cell ( where the oil was trapped) and the back of the meniscus lens is sealed ( furled) into the cell as the last surface in the cell. Is this correct ?
That's why I asked for descriptive photos of the back of the cell. Understanding the design of your objective's front lens cell is important if you are to implement a strategy to keep the oil out because you have to use oil with that objective. It makes no sense to go to all the trouble of getting the oil out of the objective , if there is no way of sealing it so oil cannot get back in.

[stjepo]

There is no oil anymore, everything is clean, but how can I seal the lens so that the oil does not enter again?

I'm sorry I couldn't take the image. What can be seen is reflected in the photograph. I've tried over and over again, top lit, bottom lit, both sides lit, and sent you the best I could.

The only thing I can think of is to seal it with silicone along the edges between the metal and the glass, very carefully.


"Based on your description however , it sounds like your front cell is a compound lens cell, not a simple cell as in the picture. It sounds like your front cell contains the meniscus lens as well, so that there is an air space inside your front cell ( where the oil was trapped) and the back of the meniscus lens is sealed ( furled) into the cell as the last surface in the cell. Is this correct ?" It is very possible but I cannot guarantee it.

[stjepo]

What I see is a kind of central glass cylinder surrounded by glass that goes from the back to the front. I wish I could have photographed it, I'm sorry.

[Hobbyst46]

The only thing I can think of is to seal it with silicone along the edges between the metal and the glass, very carefully.

Immersion oil penetrates many polymers, if left on them for many hours. Silicon sealing in general, is efficient against water, but less so against solvents and oils. Immersion oil objective should be wiped clean as soon as the immersion session is over. In addition some silicon sealants contain volatile (and odorous) components, which might perhaps be unwanted in this case.

[apochronaut]

What I see is a kind of central glass cylinder surrounded by glass that goes from the back to the front. I wish I could have photographed it, I'm sorry.

The reason it matters is that your success in sealing the objective and having it work properly is going to be determined by just how it was orignally designed and then by whether you can position the front element exactly where it needs to be in it's precise forward position and keep it there while any fixative dries. You therefore need either pressure from the back or suction from the front in order to accomplish the job depending on how the lens cell was made.

If your front cell is compound and it seems it might be , with a meniscus lens sealed in at the back, your chance of being able to do that is much lower and only front suction can be used. It seems quite a daunting procedure to me and I don't exactly know how it would be done, especially getting a cement in all the way around the perimeter from the front. It is hard enough from the back.

If it is a separation of an embedded lens, I would judge your potential success rate as close to zero, because you need to remove the existing old lens cement and use the same lens cement as the original to re-cement the lens. The fit between the two elements is extremely tight but pressure can be applied from the front. Your description of it, does sound like it might be this, especially the " surrounded by glass part".

If it is not a compound lens or an embedded lens and you can access the back of the front element from the back of the front cell ( as in the illustration you provided), then the oil would have been easily cleaned from the interspace in about an hour with swabs and ipa and cementing the front lens in place is fairly easy with pressure from the rear. I am guessing this is not the case otherwise you wouldn't have needed so much gear to extract the oil.

I have used a quality epoxy where the front lens has come loose but always the lens seat needs to be perfectly clean of debris and in exactly the same condition as it was on the day of manufacture. Dented, depressed or deformed lens seats are generally not going to allow restoration of the objective to factory specifications,
although you will get an image.
A synthetic uv cured lens cement could also be used but there needs to be some strength in the bond. The lens was originally set in a bore and a lip on the mount furled over the edge of the rear hemisphere. Thus the lens can withstand some pressure . Once the furl is broken or deformed enough to allow the lens to be loose, it sometimes can be repurposed to partially tighten the lens in place and along with some further cement make it fairly snug but usually it needs to be replaced with a ring of cement from the rear.

[stjepo]

[apochronaut]

note the edit in my first sentence. replacing determining with determined by. it makes a little more sense that way.

I dug up an old thread regarding the repair of a simpler apochromat than yours. You can see the way I sealed the front element into it's seat That one had only the front plano/convex lens in the front cell, so it was relatively easy to cement the lens into it's bore from the back, except that the lens is tiny and very easy to completely drown in cement. I apply it with the point of a needle.

viewtopic.php?t=7167

If there is a meniscus lens sealed in behind the front lens, you have to stabilize the front lens from the front OR and this is a big OR : remove the meniscus lens from it's mount, cement in the front lens from the back, then reseal the meniscus lens in exactly the same location it originally was.. I don't envy you that task. Much easier to find another broken objective with a different problem.

If it is a separated embedded front lens, I have to say you are euchered. you might have to conjure up some of that magic I referred to earlier.

[stjepo]

More images:

Back

Entrance.jpg (120.07 KiB) Viewed 1534 times

Front

front01.jpg (101.11 KiB) Viewed 1534 times

[apochronaut]

So what is loose, the small central clear lens part? I see a circumferential line in the darker grey area just outside the lighter grey area. Is that a joint between the outer glass and the central lens?

and what is causing that rectangular , more or less T.V. screen shaped image, a reflection?

[stjepo]

To be able to take those images, I used an Olympus 4X lens on the front and a PL 2.5 Leitz Wetzlar lens on the back since it was the only lens capable of getting close and giving images. The problem was how the lens illuminated and I solved it by placing it on top of 2 small methacrylate cubes, which caused that square to appear in the photograph.

What I have been able to verify is that there is a small leak on the front between the metal and the glass through which the oil/Isopropyl alcohol entered, forming that kind of collar around the central glass. I have made a sequence of the entry of the liquid that little by little evaporates.

[apochronaut]

I'm not getting a lot of insight from your pictures but your descriptions are a little better. You did say earlier that something was loose or moved. I would like to know what moves or is loose. The entire front element or just a center part of it?

[stjepo]

"The entire front element or just a center part of it?"

Yes, all the lens, as if it were floating on a raft making a perfect turn of 360 degrees in the same place but only when it had isopropyl in it. Always in the same place without bending to any side while turning around.

BUT!!!!!!! Now is dry and clean and I have verified that it does not move anymore, I thought it would move been dry or with liquid inside.

[stjepo]

A deeper analysis and at the maximum magnification of my binocular microscope shows that there is a very small movement of the lens if it is subjected to a small pressure, but it no longer rotates.

[apochronaut]

A couple of more questions. You mention that the front lens has a sort of glass surround. Does it have a more or less frosted or matte surface , kind of looking like a disperion filter?
Did it rotate as well, or just the clear central lens part?

When looking at the back side, is there another lens behind it, with a more gentle convex curve that is sealed in place?

[stjepo]

Does it have a more or less frosted or matte surface , kind of looking like a disperion filter? No;

Maybe inside is like this:

[stjepo]

The good news, I have put it back together and now it is 100X, the bad news is that the image is very blurry.

[apochronaut]

Unless you are using the correct type of oil( approx. 1.52 n) the image will be blurry. Since you still have a leak, it makes no sense to use oil.

Are you saying that the presenting rear surface when you look at the back of that front lens cell, is a plano surface?
In your rendition, what is the black layer on the front. The immersion medium?

[stjepo]

Oil EUROMEX Immersion oil nD 1.482.


I went back to check it again and yes is plano surface.

"In your rendition, what is the black layer on the front. The immersion medium?" no just part of the drawing. The metal and the lens are at the same level.