My fleabay 40x Neofluar was a bit flat - what I found...

uimike · Post by **uimike** » Fri May 03, 2013 3:25 pm

Zeiss Neofluar 40x/0.75

Am I looking at delimitation here, or something else, or a combination of things?

Because it was > than the return time, fleabay did not cover my back - and the seller (from California) isn't even listed anymore ha ha...

mike

curt0909 · Post by **curt0909** » Fri May 03, 2013 7:01 pm

Likely delamination. Unfortunately its quite common with these particular objectives. I've had a few Zeiss objectives and have seen my share of this. It can look like this with smooth ripples or it can have a sharp jagged spider web kind of look... Best way to tell for sure is with a bertrand lens. By focusing the bertrand lens through the objective you'll see where exactly the damage is.

uimike · Post by **uimike** » Fri May 03, 2013 8:26 pm

This one was all over the lens surface - I looked at it through my 3.2x
Did you ever try the xylene technique I heard someone use here (or maybe the yahoo group) - for a temporary fix?

rjlittlefield · Post by **rjlittlefield** » Fri May 03, 2013 9:53 pm

uimike wrote:This one was all over the lens surface

"surface", as in front or rear, like an external deposit? Not somewhere inside the lens?

--Rik

Pau · Post by **Pau** » Sat May 04, 2013 1:26 am

If all this stuff is at the front lens as it seems, I'm almost sure that this will be inmersion oil badly wipped but not really cleaned. Because the short working distance of these objectives if you use an oil inmersion one on a slide and you you change to the 40X you inmerse it. I'ts a very common accident. If it is oil it will be easy to remove just with a lens cleaner tissue with ethanol or a cleaning solution (ether-ethanol). Do several cleanings avoiding high pressure to prevent any solid particle to scratch ther lens. After cleaning repeat a careful inspection and test the lens with a good slide looking specially for good contrast.

Ichthyophthirius · Post by **Ichthyophthirius** » Sat May 04, 2013 4:48 am

If this is indeed immersion oil on the surface of the front lens, you should be able to clean it off.

An extensive guide to cleaning microscope lenses is provided here: http://www.icms.qmul.ac.uk/imaging/User ... oscope.pdf This is for modern Zeiss lenses.

There are many opinions on what the best solvent would be. As far as I remember Zeiss explicitly warned against using ethanol on their older lenses (sorry, can't find the reference). Acetone and Ether (=ethylether) are also very dangerous as they attack other components of the objectives.

Both Petroleum ether (= hexan) and small amounts of Xylene (never immerse the objective in solvent as xylene in particular dissolves the lens kit on older objectives) are widely considered to be save (for the lens) when applied as described in the PDF.

uimike · Post by **uimike** » Sat May 04, 2013 10:42 am

wow, lots of help! thanks Rik, Pau, Ichtio, curt.

I will triple-check (using my Zeiss stereo as well). It is on the inside element(s) of the Neofluar, not on the front element, as far as I can tell.

I unscrewed the objective, and took the picture looking from its nosepiece end - sorry I wasn't clear about it before guys.

If I had a diagram for this objective it would be easy to show. Are there Zeiss diagrams like the ones they have for for photo lenses?

Maybe the objective _is_ salvageable? (as per Pau, Ichtio) That would be cool.

unrelated note: I did clean (haid tons of fibers inside the objective) my recently acquired Lomo 20x Apo, and I am pairing it with my new (old) Olympus 15x WFK eyepices on the Zeiss Standard. Wow! this is very dangerou$$

uimike · Post by **uimike** » Sat May 04, 2013 10:47 am

Icht,

is lighter fluid a decent alternative?

Pau · Post by **Pau** » Sun May 05, 2013 2:33 am

uimike wrote: I will triple-check (using my Zeiss stereo as well). It is on the inside element(s) of the Neofluar, not on the front element, as far as I can tell.

Very extrange. (To be sure, just touch a bit the front element with a kleenex and the dirt would change its distribution)
If it's inside the objective (

How did come all this dirt inside?), just return it.

uimike · Post by **uimike** » Sun May 05, 2013 8:07 am

Hi Pau,

Strage it is! - I touched the front element gently with optical tissue and some IPA, and took a pic with my Stereomicroscope - it is inside.

Alas, the seller is not on *bay anymore

Ichthyophthirius · Post by **Ichthyophthirius** » Sun May 05, 2013 8:48 am

Hi Mike,

From what you have said, this seems to be delamination then (or some other kind of unusual damage - hard to say from the distance, but the concentric rings point towards delamination).

Unfortunately, there is very little you can do. There are very few people out there who can dis-assemble the objective (probably 6 lenses in there!), separate the faulty pair, re-cement and re-align them. However, since that is a relatively cheap objective (might not feel that way) that would cost much more than it is worth. You might have to get another one; it's a great objective to have!

OT: Not sure about the lighter fluid; might work but is not guaranteed as it may or may not contain impurities. "Petroleum ether" is a mixture of pentans/hexans that is available in purified form relatively cheaply (e.g. from pharmacies), so it is the recommended cleaning agent.

Pau · Post by **Pau** » Sun May 05, 2013 10:19 am

uimike wrote:Alas, the seller is not on *bay anymore

Even so, if the listing specified "returns accepted" and you're in time you can open a case in ebay and ask for "ebay buyer protection".

uimike · Post by **uimike** » Sun May 05, 2013 7:35 pm

Hi Pau - unfortunately I'm out of the coverage period.

Ichtyo., I will definitely check the drugstore - yeah, nothing I can do... I am getting an Olympus SPlan 20x as a replacement.

If I can't fix the Neofluar, or fix it economically, then I might as well try and dismantle it completely - just for fun

Ichthyophthirius · Post by **Ichthyophthirius** » Fri May 10, 2013 9:12 am

Hi Mike,

Just to re-itterate the point, I have finally found a reference on cleaning older microscope optics.

In this instruction booklet for the Leitz Orthoplan http://www.leitz-ortholux.de/pdf/67_anleitung.pdf the company recommended destilled water, petroleum ether or xylene and warns three times against any use of ethanol (twice in bold print), pp. 9 + 11! The same applies to the older Zeiss optics.

uimike · Post by **uimike** » Fri May 10, 2013 10:32 am

Ichthyophthirius,

great document - thanks! (btw, that ortholux is sooo beautiful)

I bought some xylene, still have to buy some petroleum ether.

I guess I am a bit confused about xylene vs lenses - in older Zeiss microscopes some of the lens groups were cemented together with Canada Balsam - wouldn't xyelene dissolve this?