Olympus NIC/Phase Contrast condenser repair question

[Ryanb]

Hey folks! I recently acquired an NIC/Phase contrast condenser and am extremely happy. The only downside is that the condenser glass is broken
Is there any hope of saving this and making it functional again? Maybe sending it to Olympus and they have someone who can repair it?

Thanks so much and I appreciate any and all feedback!

[PeteM]

That's quite a break. Is the DIC prism under that OK?

In any case, the lens looks much like an older Olympus NIC condenser from the Vanox-BH era rather than the most recent BH2 versions. If so, the screw-on lens from an old 1.4na Olympus oblique condenser might fit. If you can provide the exact mm or inch diameter of the threaded portion, I can check if the diameters match up. If you have a metric thread gauge, check that as well.

It's possible an Olympus dealer might have one of these lying around. Ebay and the Olympus Facebook group are other sources. It's worth contacting Olympus a.k.a. Evident, but I'll be surprised if they are of help.

Have you been able to source an upper sliding prism and its intermediate housing? If not, that prism is usually difficult and pricey to find. You might want to hold off finding a new condenser lens top until you secure that.

[apochronaut]

One good thing is that the top lens of a condenser is usually a single piece of glass or at best contains a thin plane sheet sandwiched on top of the lens, not really a doublet. There is no aplanatism or achromatism built into the top lens just the N.A. of the condenser. Lens suppliers sometimes have plano/convex lenses with a severe enough convex curvature to be 1.4 N.A.. If the diameter is the same and the curvature the same it should work. The strain free nature of the lens is secure if there is no cement joint, which you would be able to see.
I was able to rebuild a couple of 1.30 achromats in the past by sourcing 1.3 top lenses of the correct diameter.

[Hobbyst46]

I have an old condenser top lens, Olympus achromat aplanat 1.4, in fairly good condition I think. Looks similar to yours and perhaps will fit your condenser. Thread diameter 35mm. Top glass diameter 16.4mm. Glass looks clean, except for two tiny chirps (diameter, say <0.5mm) on the top glass. I believe they will not significantly affect the image but cannot guarantee it. Thickness 20mm. If interested, please PM me.

[Ryanb]

That's quite a break. Is the DIC prism under that OK?

In any case, the lens looks much like an older Olympus NIC condenser from the Vanox-BH era rather than the most recent BH2 versions. If so, the screw-on lens from an old 1.4na Olympus oblique condenser might fit. If you can provide the exact mm or inch diameter of the threaded portion, I can check if the diameters match up. If you have a metric thread gauge, check that as well.

It's possible an Olympus dealer might have one of these lying around. Ebay and the Olympus Facebook group are other sources. It's worth contacting Olympus a.k.a. Evident, but I'll be surprised if they are of help.

Have you been able to source an upper sliding prism and its intermediate housing? If not, that prism is usually difficult and pricey to find. You might want to hold off finding a new condenser lens top until you secure that.

Wonderful advice Pete. I will try to measure everything and get back to you with the measurements! I’ll reach out to Olympus as well and have started looking for that upper slider as I know that’s most certainly not cheap. I did find this and yet I’m not sure what it is. Ever seen this?

IMG_7369.jpeg (58.82 KiB) Viewed 4788 times

I have a vanox AH and a BH2 so hopefully no matter what generation the condenser is, I can still make use of it. Thanks again

[Ryanb]

One good thing is that the top lens of a condenser is usually a single piece of glass or at best contains a thin plane sheet sandwiched on top of the lens, not really a doublet. There is no aplanatism or achromatism built into the top lens just the N.A. of the condenser. Lens suppliers sometimes have plano/convex lenses with a severe enough convex curvature to be 1.4 N.A.. If the diameter is the same and the curvature the same it should work. The strain free nature of the lens is secure if there is no cement joint, which you would be able to see.
I was able to rebuild a couple of 1.30 achromats in the past by sourcing 1.3 top lenses of the correct diameter.

This is wonderful news!! I would not have thought to do this. So it is good or bad news to see a cement joint? I have started looking for replacement lenses now and maybe this will be the key! Thanks so much! It seems very few other manufacturers had 1.4 condensers at least from a quick eBay search. I’ll keep you posted

[PeteM]

The item marked "AN-2" is an analyzer (a polarizer) meant to fit between the head and stand of a microscope. Recollection is dim, but I believe it fits an Olympus BH or BH2. It can be used for simple polarization, without the necessity of adding an intermediate piece and its 1.25x magnification.

[apochronaut]

One good thing is that the top lens of a condenser is usually a single piece of glass or at best contains a thin plane sheet sandwiched on top of the lens, not really a doublet. There is no aplanatism or achromatism built into the top lens just the N.A. of the condenser. Lens suppliers sometimes have plano/convex lenses with a severe enough convex curvature to be 1.4 N.A.. If the diameter is the same and the curvature the same it should work. The strain free nature of the lens is secure if there is no cement joint, which you would be able to see.
I was able to rebuild a couple of 1.30 achromats in the past by sourcing 1.3 top lenses of the correct diameter.

This is wonderful news!! I would not have thought to do this. So it is good or bad news to see a cement joint? I have started looking for replacement lenses now and maybe this will be the key! Thanks so much! It seems very few other manufacturers had 1.4 condensers at least from a quick eBay search. I’ll keep you posted

I would follow up Hobbyst46's offer as a first choice. He may have the exact lens you require.
I don't know which companies used a top cover glass on their condenser lenses but the one I do know of used it on a 1.4 N.A. achromat aplanat. I have wondered about this and it may simply have been a design to facilitate the easy repair of the top surface if scratched or even possibly a hardened surface. I don't think the presence of a cemented on upper surface is of consequence but it is unlikely to be found on a replacement lens. Any I have seen were one piece of glass.
1.4 condensers were/are very common. Just about every microscope mfg. has made them at one time because they are necessary for objectives above 1.3, which are also very common. They just aren't as common as 1.25 condensers , which outnumber them 100 fold.
The key is that the diameter of the upper portion of the top lens must be the same as the one being replaced and the top to bottom length the same or if slightly larger, then the top to bottom length proportionately so.
I do have a few 1.4 N.A. condenser housing blanks which include the upper lens only. If you could get an idea of the diameter of the upper surface of your lens and post it, I can get one of these in my hand and measure it.

[woyjwjl]

older Olympus NIC condenser from the Vanox-BH

Coincidentally, I happen to have both the Vanox AH and BH2 DIC kits at the same time. It is safe to say that their top lens components are fully compatible and do not require any modifications.