Reichert Zetopan Polyphos Condenser

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dolmadis
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Reichert Zetopan Polyphos Condenser

Post by dolmadis »

Hi

Need some help/advice.

I have a Zetopan plus Anoptral objectives.

I have been made a gift of a Polyphos Condenser which has the top lens missing. So no "skin in the game" !

It is going to get to me in a few weeks so I am turning to the group to ask what I can do with it noting that it is not confined to phase but has the lighting opportunities of a Heine.

So with no top lens?

Is there an alternative top lens in any fashion?

Worth any effort?

The third is a nice paper weight which will roll across the desk quite nicely.

Thanks for any comments.

BR

John

Ichthyophthirius
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Post by Ichthyophthirius »

Hi John,

How much is missing? It seems that several things can be taken off: http://www.microbehunter.com/microscopy ... php?t=4143

Do you know the Heine top lens? It's just a more or less hemispherical lens. In that case it might be possible to find a replacement that works satisfactorily.

In case of the Polyphos, you need to find out what the original front lens (assembly) looks like and try replacing it with an optic of similar design.

Regards, Ichty

dolmadis
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Post by dolmadis »

Hi Ichty

Thank you.

I shall have to wait until the item is in hand to see what exactly is missing but the description was "but TOP (upper) LENS IS MISSING !!!"

I have rejuvenated the thread you referred to at that link in case I can get some more information whilst I wait.

I noticed that our member zzffnn (Fan) was also requesting information and in part about the top lens and whether it unscrewed.

Fan may know more now and I hope that he will contribute here or there.

Might be that another member here has one or knows someone who does so that the characteristic of the top lens can be described.

I have found a few photographs on Google but no line drawings.

BR


John

zzffnn
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Post by zzffnn »

John,

Sorry, I don't have much to add on the Polyphos. I gave up on pursuing the Polyphos, because I failed to obtain any additional information or a reasonably priced sale.

So I bought a Leitz Heine with NA 1.4 top (oil immersion) lens instead and like it very much.

The Heine is rare too, but I have received two offers and gladly went with one of them. I like the Heine in that it provides a good compromise between convenience, image resolution and contrast/3D relief effect, at a single focus plane (without requiring focus stacking, when Heine COL oblique or darkfield is used).

I think the Polyphos will provide you similar effects, though its highest NA may be limited, without its top lens. My microscope is in storage, but if I remember it correctly, the Heine without top lens (which unscrews) will provide widest illumination cone at about NA 0.95. I don't know what NA the Polyphos can provide without top lens.

The Heine is very convenient to use, because it allows me to very quickly switch between darkfield and oblique and also adjust oblique illumination cone NA, by moving the internal mirror up or down with a geared control knob.

I consider the Heine condenser a compromise, as its imagery may not be the cleanest (you get donut bokeh kind of shadow effect), when you use it at maximum oblique NA. I reduce that donut bokeh effect by reducing the illumination cone NA slightly (by lowering the mirror). Also the Heine needs a lot of light to provide bright images at high NA.
Last edited by zzffnn on Mon Feb 12, 2018 6:31 am, edited 1 time in total.

dolmadis
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Post by dolmadis »

Thanks Fan.

It looks like the Polyphos is a write off from the recent photos that I have seen.

John

dolmadis
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Post by dolmadis »

Hi All

I now have the condenser in hand and I can see the damage to just the top lens more clearly.

The rest is complete and working.

I would welcome comments please !!

(I do not have a mount to try it out)

BR

John

Image

Image

Thanks


John

ChrisR
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Post by ChrisR »

:-& What's its diameter?

FL??
Chris R

dolmadis
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Post by dolmadis »

Hi Chris

https://www.worthpoint.com/worthopedia/ ... -307231388

FL?

Diameter of top lens of condenser is by eye, 1.9mm

BR


John

zzffnn
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Post by zzffnn »

Please give it a try, John. It may work just fine.

You can mount the condenser on a glass slide or two, say with mounting putty. The key is centering adjustment for your most powerful objective. And keep the top lens flat.

If the glass elements breakage really affects image, you may use some hard durable glass cement, very carefully/little by little, one lens by one lens (don't pour on too much). I don't know a hard durable glass cement though, as mine feels like silicone in texture.

I think ChrisR was asking about focal length.
Last edited by zzffnn on Mon Feb 12, 2018 6:31 am, edited 1 time in total.
Selling my Canon FD 200mm F/2.8 lens

dolmadis
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Post by dolmadis »

Thanks for the idea of a quick mount, Fan.

There is very little written about this condenser and I have not found a manual or instruction for use. But the rise and fall of the internal mirror mechanism is complete and working.

ChrisR asked about FL - Focal Length.

I have no idea about the Focal Length of this Condenser. How would you measure this please?

And once found how will this add thoughts/conclusions to the question of useability with the broken top lens?

Would there be any benefit in using a high RI mounting medium for diatom slides to stabilise the breaks?

BR


John

zzffnn
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Post by zzffnn »

John,

Mounting medium may leak inside between lens elements and change optical property. You want something that dries almost instantly to prevent leaking. And you want to repair the outside surfaces first in situ, if you have to repair it (it is difficult to put back broken glass pieces exactly as it was).

FL info may help finding an alternative top lens, if you have to go that way. I don't know how to measure FL.
Selling my Canon FD 200mm F/2.8 lens

dolmadis
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Joined: Wed Dec 07, 2011 1:51 pm
Location: UK

Post by dolmadis »

Thanks Fan.

As the top lens is removable as in the photos I thought that using a very little of a high RI medium might be OK because there is no chance of leakage into the mechanism once the top is unscrewed to one side.

Anyone know how long they take to set? A fast setting one?

The glass is completely in situ as in the fragments so I am giving priority to thinking about stabilisation before a try out and risk of a tumble.

Any input from Members who know about high RI media welcome.

BR


John

zzffnn
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Post by zzffnn »

John,

Can you be 100% sure that the top lens has only a single element, not 2-3 elements with air gap in between? If the later, high RI media leaking in between may mess up optical path by filling the air gap.

I would guess the top lens is a single element, as Heine's top lens appears to be (but it looks quite different than that of your Polyphos). So it is better to be sure than sorry.

Best,
Fan
Selling my Canon FD 200mm F/2.8 lens

Pau
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Post by Pau »

I would test the condenser as is it and if bad test other condensers upper lens with similar NA
In case of using cement to glue the broken lens you do want one with the same RI than optical glass like Canada Balsam or a more modern equivalent to maintain the optical continuity, if different the result would not be much better than the air gaps in the fractures.
Pau

dolmadis
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Post by dolmadis »

Hi Pau

Any thoughts on Windshield Repair Resin - Low Viscosity Resin 15cc RLVAF-15?

http://www.gtglass.eu/15ml_windshield_repair_resin_en

Fan, as the cracks are coincident top to bottom I conclude no air gap.

BR

John

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