I doubt this was an intentional act by someone. I understand from Zeiss reps and other sources that oil leakage into the objective barrel usually happens over time. However, I can imagine that a LOT of oil getting into the side crevices would show up in the bottom lens fairly quickly, but I cannot imagine someone would go out of their way to pour oil into the side crevices (Unless they are a knowledgeable microscopy bandit that knows how to damage lenses on purpose).

We use little hair "scrunchies" to catch excess oil on our inverted microscopes as well (I even rotate colors to celebrate relevant Holidays). Besides regularly cleaning the front lenses after use, I usually take off the scrunchies about once a week and thoroughly soak/wipe them with 95% ethanol. Maybe once a month I replace them, as they do get nasty. I am sometimes surprised by the translucence of the oil that makes its way on the side of the objective. Even if I see no oil "trail," I can usually feel the oil.

I rarely let oil sit on a lens for more than a few hours (i.e. avoid overnight oil sitting). As always, the best way to prevent any damage is to regularly remind users that they need way less oil than they think!

It seems possible that there could be invisible damage in/around the front lens, which caused the oil to leak in. Then again, I have a hard time wrapping my head around how it got to the bottom lens and possibly surpassing other optics inside.

Loren

-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]] On Behalf Of Christian Elowsky
Sent: Monday, April 04, 2016 10:12 AM
To: [log in to unmask]
Subject: Re: Oil on back focal plane of objective

Craig,

You just made my day, if not month with this suggestion!

Thank you!

Christian



-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]] On Behalf Of Craig Brideau
Sent: Monday, April 04, 2016 11:54 AM
To: [log in to unmask]
Subject: Re: Oil on back focal plane of objective

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
Post images on http://www.imgur.com and include the link in your posting.
*****

I still stand by my recommendation of cloth hair scrunchies on the objectives. It catches any oil drips running down the side of the objective on inverted scopes. It won't save you from oil leaking into the spring-loaded tips but it at least keeps it from soaking into the optics under the objective. You can even use them for color coding!
http://previews.123rf.com/images/belchonock/belchonock1108/belchonock110800172/10220322-hair-scrunchies-on-brown-background-Stock-Photo.jpg

Craig Brideau

On Mon, Apr 4, 2016 at 9:31 AM, David Claypool <[log in to unmask]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> To All,
>
> This is a somewhat common problem with oil immersion objectives on 
> inverted microscopes and is not limited to any one brand or manufacturer.
>
> If excess oil is not removed after using the objective m(a simple wipe 
> with lens tissue will suffice), gravity will eventually cause the oil 
> to run down the spring loaded front lens barrel into the objective. 
> Over time enough oil will build up in the objective, so that it can 
> find its way between the inner lens elements.
>
> The other scenario is if the front lens of the objective has been 
> crashed into a specimen holder or the underside of a x-y stage. This 
> can cause the seal around the front lens to develop a microcrack and 
> the immersion oil will find its way into the objective.
>
> Either of the above damage is usually repairable by the manufacturer, 
> but not under warranty.
>
> I have seen people use a piece of a pipe cleaner wrapped around the 
> objective to catch the excess oil, but you need to remember to change 
> it regularly.
>
> David J. Claypool
> Digital Imaging Product Manager
> Micro Video Instruments
> Office: 800-875-2041 x5221
> Cell: 603-809-5342
> [log in to unmask]
>
> > On Apr 4, 2016, at 11:16 AM, Zdenek Svindrych <[log in to unmask]> wrote:
> >
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images on http://www.imgur.com and include the link in your
> posting.
> > *****
> >
> >
> > Hi.
> > To me it seems very unlikely someone would do that on purpose. It's 
> > more likely that some greenhorn user misunderstood the sentence 
> > "don't forget
> to
> > apply oil to the oil immersion objective" or something like that in 
> > your manual (I'm sure you don't specifically note that it's not 
> > necessary to unscrew the objective from the turret to do that :-).
> > But seriously, if the oil got inside the objective through the front 
> > lens seal and found its way to the last lens, the lens is probably 
> > full of oil and can't be fixed. You may try to clean it and test 
> > whether it performs well, or ask the vendor whether they can check 
> > it for you (and ask how
> much
> > it would cost!). If you have service contract, they might do it for 
> > you
> for
> > free, you might even be covered by some sort of warranty.
> >
> > I doubt oil could get there from the lens threads through capillary
> action,
> > and oil is not superfluid...
> >
> > Good Luck!
> >
> > zdenek
> >
> >
> > ---------- Původní zpráva ----------
> > Od: Gary Laevsky <[log in to unmask]>
> > Komu: [log in to unmask]
> > Datum: 4. 4. 2016 10:39:50
> > Předmět: Re: Oil on back focal plane of objective
> >
> > "*****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images on http://www.imgur.com and include the link in your
> posting.
> > *****
> >
> > Hi All,
> >
> > To be clear, if oil was leaking down the barrel of the objective, 
> > and
> ended
> > up on the center of the back focal plan, there would be a trail from 
> > the edge, right?
> >
> > This was a solitary drop on the center of the back.
> >
> > I'm trying to find someone that will correct me from thinking this 
> > was a malicious act.
> >
> > Best,
> >
> > gary
> >
> > On Mon, Apr 4, 2016 at 5:48 AM, Gary Laevsky 
> > <[log in to unmask]>
> > wrote:
> >
> >> Hi All,
> >>
> >> Trying not to be cynical here, but, can anybody please explain to 
> >> me if there is a way for a drop of oil to end up on the center of 
> >> the back
> focal
> >> plane of an objective (oil immersion objective) on an inverted 
> >> scope. No smear from the side.
> >>
> >> Thanks.
> >>
> >> --
> >> Best,
> >>
> >> Gary Laevsky, Ph.D.
> >> Director, Confocal Imaging Facility Nikon Center of Excellence 
> >> Dept. of Molecular Biology Washington Rd.
> >> Princeton University
> >> Princeton, New Jersey, 08544-1014
> >> (O) 609 258 5432
> >> (C) 508 507 1310
> >
> >
> >
> > --
> > Best,
> >
> > Gary Laevsky, Ph.D.
> > Director, Confocal Imaging Facility
> > Nikon Center of Excellence
> > Dept. of Molecular Biology
> > Washington Rd.
> > Princeton University
> > Princeton, New Jersey, 08544-1014
> > (O) 609 258 5432
> > (C) 508 507 1310"
>


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