Clean objective lens

Revision as of 16:52, 16 March 2011

Objective lens cleaning is very inmportant.

(organise and add more stuff here)

A question we wish was more common:

"When do you offer the next "lens-cleaning-training-session"? I would be very interested to attend!"

Anyone who wants to learn how to really clean a lens should just come and ask, and we will give you the basic / advanced version as you prefer. You can even book one of us for 30 min to secure your training slot! Bring you friends, and your dirty lenses.

The lens IS the microscope.

Dirty lens = crappy image.

as can be seen here:
https://ifn.mpi-cbg.de/wiki/ifn/index.php/Gallery#Cleaning_an_objective_makes_sense

You need to know how to clean it - and really clean it, not just drag a wet lens tissue over it.
Never assume the lens is cleaned properly by the last person - clean it before you start.

The problem:

"Everybody I ask seems to have a slightly different lens cleaning protocol depending on the type of the lens (oil/water/air), the manufacturer and the weather"

"I tend to use the Zeiss "protocol", but what is the current state of art at the CBG?... what is that exactly...?"

Good to know

An eye piece from any microscope, inverted, works as a magnifying glass - you can get close up to your dirty lens and see if you really cleaned it.

What to clean a lens with

Use only proper lens cleaning tissues - they are available in stores.

Never ever ever use kimwipes, these will scratch glass.

Immersion lenses (oil / Water /water oil/ glycerol etc)

Zeiss immersion (oil/water) lenses:
on the Zeiss confocal and widefields: 70% ethanol - folded over lens cleaning tissue - keep going until the lens is clean as seem by an inverted eyepiece as a magnifying glass.

Olympus immersion Lenses:
on the spinning disks : 70% ethanol , then finish off with ethanbol/ether

Olympus lenses on the DVcore:
chlorophorm (care - gloves please) saturated Q-tip to dissolve and get most of the oil into the Q-tip (no scrubbing , just rolling), then finish off with lend cleaning tissue folded over with a drop of ethanol/ether mix enough times to see its clean as seen under the stereo microscope with a ring light. Olympus also recommends a Corning solution whoch we have - for stubborn stains... its a bit nbasty, but we have the data sheet.

Leica and Nikon immersion lenses:
- 70% ethanol.

Air lenses

should never get oil on them (...muffled laughter...) , so a manual air puffer can remove any dust (the spray can aerosols blow crap onto your glass, don't use those) To remove oil from an air lens ... try 70% ethanol... then more serious solvents as above until you get it clean.

General points

• Even though, usual, you only need to clean the top lens, sometimes (miraculously) there appear fingerprints on the back lens. This is a bit harder to reach then the front lens, but in principle the same cleaning procedures apply.

• Keep the objective body clean, too!!! Any fluid on the body is prone to run into the objective at some point. When this happens there is no way to clean the objective yourself anymore - you will have to send it to the manufacturer for professional (expensive) cleaning.

Nice story:
Zeiss tell us the urban myth that they once got a lens for repair that was full to bursting with immersion oil .... apparently the user took the immersion instruction literally and filled it up.

• It might be obvious, but don't drop your objective! There is a very fragile array of lenses inside it and misalignment of these will impair the objectives function if not even render it useless.

• Don't scratch the lens! Any tiny damage will affect your final image.

• Beware - aggressive solvents may dissolve the glue holding the lenses in place in the metal cylinder. So go easy, always start with the most gentle cleaning reagent and slowly work your way up.

• If you are unsure about your objective's performance: this is defined over the point spread function of the lens and can be measured by imaging sub resolution beads. We have those-so just ask.

"What about some of you guys write a "white paper" on the topic to help avoid confusion? I think that would be extremely useful for all of us here - given the importance of high quality imaging and the price of the optics."

All manufacturers have info like this available (website perhaps)... but opinion varies even between different people at the same company.
This is what Zeiss says: The Clean Microscope

W2 DVcore special cleaning protocol:

Dear All DV core users and lens cleanliness freaks,

New lens cleaning protocol:

From Now on please finish off the lens with Ethanol/Ether (not Ethanol/Water as previously taught to you)

4:1 Ether:Ethanol mix works better then the &0% Ethanol mix for removing the last greasy residues that the chloroform leaves behind. It is a better grease solvent and evaporates faster and leaves less residue on the lens. Sometimes 70% ethanol will remove a stain that the 4:1 Ether:Ethanol does not.

always use the stereo microscope with the Olympus ring light (not the octopus lights) so you can really see the dirt easiest.

For stubborn stains we also have the Olympus recommended Corning cleaning solution - just ask.

Happy imaging (and lens cleaning before AND after!)

your LMF team