Re: chromatic aberration

Posted by mmodel on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Concentrating-bacteria-cells-for-microscope-visualization-tp6519025p7134081.html

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

I use fluorescent multicolor beads on a coverslip. But even before, I have noticed that when I am looking at cells in transmission, I see different things depending on the filter. You may argue that with cells, there is spherical aberration, etc but with beads there shouldn't be any. So I thought that perhaps low-NA objectives are generally less well corrected for longitudinal chromatic aberration? Even when of the planapo type. Olympus does not provide any numbers, just says that the objectives are 'excellent".

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Martin Wessendorf
Sent: Wednesday, December 28, 2011 4:26 PM
To: [hidden email]
Subject: Re: chromatic aberration

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

How are you measuring the aberration?  Beads?  Reflectance?

On 12/28/2011 2:46 PM, MODEL, MICHAEL wrote:

> Olympus. Their higher-NA objectives are fine
>
> -----Original Message-----
> From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Martin Wessendorf
> Sent: Wednesday, December 28, 2011 3:25 PM
> To: [hidden email]
> Subject: Re: chromatic aberration
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Hey, Mike--
>
> On 12/28/2011 2:01 PM, MODEL, MICHAEL wrote:
>
>> Both of our 10/0.4 planapo objectives have a bad longitudinal chromatic aberration between blue and far red (2.5 um axial shift with correct coverslip). Is this normal for low-power objectives?
>
> What manufacturer?  Not to trash any particular brand but I've seen
> problems that bad on 60x oil objectives from some makers and would
> expect a 10x objective to be even worse.
>
> Martin

--
Martin Wessendorf, Ph.D.                   office: [phone]
Assoc Prof, Dept Neuroscience                 lab: [phone]
University of Minnesota             Preferred FAX: [phone]
6-145 Jackson Hall, 321 Church St. SE    Dept Fax: [phone]
Minneapolis, MN  55455                    e-mail: [hidden email]