Re: Oil vs water objectives

Posted by George McNamara on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Oil-vs-water-objectives-tp7579114p7579129.html

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Hi Jim and listserv,

Jim wrote, "I am convinced that it was because they just didn't want to
take the time to adjust the collar properly. "

An additional explanation is that the microscope vendors have done a
poor job making critical microscope features - such as the correction
collar - easy to reach and use. Of course the customer buying an
anti-ergonomic microscope are also contributing to the problem.

One solution of course is to "automate everything" - which simply
changes the issue from being physically out of reach physically to one
of budget.

The vendors should be able to design microscopes - and nanoscopes - that
have excellent ergonomics and optics, and customers should take the time
to buy such microscopes.

Another option with respect to S.A. is to move the correction outside
the microscope, as with the mSAC

https://www.intelligent-imaging.com/msac.php

though this makes me wonder what happens if the mSAC is used with an
objective lens whose "correction" collar is (badly) misadjusted.

George


On 10/4/2012 7:26 PM, James Pawley wrote:

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>
> Hi all,
>
> Looks like you have received a lot of good advice, but I would like to
> add one thing.
>
> Yes, do a test BUT don't forget to be very careful in adjusting the SA
> correction collar on the water lens. )Find a point object: focus up
> and down and adjust for symmetry (i.e., for the same image a little
> above focus as a little below focus. DON'T just try to "make it
> sharper!" The collar changes the focus plane.)
>
> The collars usually have markings in terms of the coverslip thickness
> that they are designed to correct for. One can easily see the
> difference created by mis-adjusting a 1.2 NA objective by 2
> µm-of-glass-replaced-by-water (my favorite unit for "measuring" SA).
>
> When modern water objectives first emerged in the early 1990s, many
> folk bought them and then went back to their oil objectives and I am
> convinced that it was because they just didn't want to take the time
> to adjust the collar properly.
>
> Because, if you do adjust it properly, you will get better (brighter?
> higher resolution?) images of aqeous specimens beyond about 3 µm
>
> Best,
>
> Jim Pawley,
>
> Near Harbin, China.
>
>
>
>> Make sure the coverslip is orthogonal to the image axis with your
>> water objective.
>>
>> A common aberration with water-immersion objective lenses.
>> J Microsc. 2004 Oct;216(Pt 1):49-51.
>> http://www.ncbi.nlm.nih.gov/pubmed/15369482
>>
>> Doug
>>
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> Douglas W. Cromey, M.S. - Associate Scientific Investigator
>> Dept. of Cellular & Molecular Medicine, University of Arizona
>> 1501 N. Campbell Ave, Tucson, AZ  85724-5044 USA
>>
>> office:  AHSC 4212         email: [hidden email]
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>>
>> -----Original Message-----
>> From: Confocal Microscopy List
>> [mailto:[hidden email]] On Behalf Of Steffen Dietzel
>> Sent: Thursday, October 04, 2012 7:30 AM
>> To: [hidden email]
>> Subject: Re: Oil vs water objectives
>>
>> *****
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>>
>> I second Michael's comment.
>>
>> Apart from that, when you have an aqueous(!) preparation, spherical
>> aberration decreases image quality faster for the oil objective. So,
>> directly behind the coverslip the oil objective (1.4) will give you
>> the better image due to the higher NA, at some depth both objectives
>> will give you similar quality and beyond that, the water immersion
>> will be better.
>>
>> I seem to remember that for oil 1.4 and water 1.2 the crossing point is
>> 10-20 µm into the sample.
>>
>> If you have the Handbook laying around, check the chapter on Lens
>> aberrations. Chapter 20 by Hell and Stelzer in the second edition,
>> chapter 20 by Egner and Hell in the 3rd edition.
>>
>> Needles to say that all above considerations assume that both
>> objectives have the same transparency for excitation and emission
>> wavelengths - which they probably don't. So we are back at Michael's
>> comment: You've got to test it. Beads attached to the coverslip and
>> the slide (various preparations with various distances between the
>> two) give good test objects.
>>
>> Steffen
>>
>> On 04.10.2012 15:15, Gabriel Lapointe wrote:
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>>>
>>>  Hi,
>>>
>>>  I have a user who insist that using a 1,27NA water immersion objective
>>>  is brighter and would give better images than using a 1,4NA oil
>>>  immersion. I understand that deeper into the media that would be true.
>>>  But, in that particular case, we are talking about imaging GFP at less
>>>  than 100 micron away with a spinning disk.
>>>
>>>  So, I was wondering at which distance from the coverslips do we start
>>>  seeing benefits of using a water immersion objective over an oil
>>>  objective in aqueous media.
>>>
>>>  Thanks for your help.
>>>
>>>  Sincerely
>>>  *Gabriel Lapointe, M.Sc.*
>> > Lab Manager / Microscopy Specialist
>>>  Concordia University, Biology Department
>>>  7141 Sherbrooke St. West SP 534
>>>  Montréal QC H4B 1R6 Canada
>>>  [hidden email]
>>>  cmac.concordia.ca
>>>  http://gabriellapointe.ca
>>>
>>
>>
>> --
>> ------------------------------------------------------------
>> Steffen Dietzel, PD Dr. rer. nat
>> Ludwig-Maximilians-Universität München
>> Walter-Brendel-Zentrum für experimentelle Medizin (WBex) Head of
>> light microscopy
>>
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>
>