Nipkow Disk Pinholes question

[O'Malley, Donald]

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http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

 Hi Folks,

I am wondering if the pinhole-aperture diameter in the Nipkow
disk can be changed in instances where one might wish to
open the aperture to trade away some z-resolution in
exchange for increased signal?  I imagine this could be done
by switching between disks with different sized pinholes, but
am not sure if this would be fast and easy enough such that
one could go "back and forth" during e.g. a physiological
experiment.  This seems an area where traditional point-
scanning confocals may have an advantage.

Also, are there different disks for different magnification
objectives?  Is the right disk automatically selected on
such instruments?

thanks for any info.

Don O'Malley
Northeastern University

[RICHARD BURRY]

Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal Don
 
This is a problem with the Nipkow (Yokawaga) spinning disk, it is optomized for N.A. 1.40 which makes is difficult to use for lower mag objectives.  We are currently setting up the Visitech Infinity3, a 2D Array scanning confocal that has 7 different sets of pinholes.  This technology appears to have an advantage over the spinning disk and maintain the highest possible resolution. 
 
You also might consider the Olympus DU spinning disk with the changable disks for different objectives.  This technology is different from the Nipkow disk using glass disks with squares for transmitted light.  The DU works well with low mag objectives and bright samples.
 
Dick

Richard W. Burry, Ph.D.
Department of Neuroscience, College of Medicine
Campus Microscopy and Imaging Facility, Director
The Ohio State University

----- Original Message -----
From: "Donald M. O'Malley" <[hidden email]>
Date: Thursday, May 15, 2008 4:07 pm
Subject: Nipkow Disk Pinholes question
To: [hidden email]

> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
>  Hi Folks,
>
> I am wondering if the pinhole-aperture diameter in the Nipkow
> disk can be changed in instances where one might wish to
> open the aperture to trade away some z-resolution in
> exchange for increased signal?  I imagine this could be done
> by switching between disks with different sized pinholes, but
> am not sure if this would be fast and easy enough such that
> one could go "back and forth" during e.g. a physiological
> experiment.  This seems an area where traditional point-
> scanning confocals may have an advantage.
>
> Also, are there different disks for different magnification
> objectives?  Is the right disk automatically selected on
> such instruments?
>
> thanks for any info.
>
> Don O'Malley
> Northeastern University
>
>
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[Farid Jalali]

Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal Hello Don,
I have an Olympus DSU on their IX81 frame. There are disks with different slit widths that technically correspond to a particular objective lens. I have not been able to get an answer from Olympus as to the thickness of the optical section one gets with a particular disk- I would have to likely determine this myself. In practical terms it takes about 5-10 minutes to change the disk, opening the housing, loosening the disk motor, changing disks etc. In practical terms I have not seen a marked difference in image quality or optical sectioning ability when using the disk that is meant for the 60X1.42NA with the 100X1.4NA or vice versa. I have not used the DSU with lower mag/ lower NA objectives as the disk does reduce the effective illumination quite dramatically.

The Olympus DSU has 4-5 different disks for different magnification objectives. The disk is an array of horizontal and vertical slits that when spinning at high speed (3000 rpm), generates thousands of 'virtual pinholes' to effectively optically section your sample. The disk image must be in focus and there is an adjustment for this, otherwise the optical sectioning goes to hell.

Two cents delivered.
Best Regards
Farid

On Thu, May 15, 2008 at 4:07 PM, Donald M. O'Malley <[hidden email]> wrote:

Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

 Hi Folks,

I am wondering if the pinhole-aperture diameter in the Nipkow
disk can be changed in instances where one might wish to
open the aperture to trade away some z-resolution in
exchange for increased signal?  I imagine this could be done
by switching between disks with different sized pinholes, but
am not sure if this would be fast and easy enough such that
one could go "back and forth" during e.g. a physiological
experiment.  This seems an area where traditional point-
scanning confocals may have an advantage.

Also, are there different disks for different magnification
objectives?  Is the right disk automatically selected on
such instruments?

thanks for any info.

Don O'Malley
Northeastern University

--
Farid Jalali MSc
Senior Research Technician- Lab Manager
Applied Molecular Oncology/ Princess Margaret Hospital
Radiation Medicine Program/ STTARR Program
Toronto, Canada
416-946-4501 X4351 (Princess Margaret Hospital)
416-581-7754 STTARR at MaRS Building
416-581-7791 STTARR Microscopy Suite

[Rietdorf, Jens]

Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

Hi Don,

Another way to change the pinhole size than changing the disc is to
change the magnification of your microscope, because pinholes are
projected by the microscope optics. We use an optovar on our Yokogawa
SD. Bear in mind changing mag will also affect sampling frequency in
camera based systems.

Cheers, jens

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On
Behalf Of Donald M. O'Malley
Sent: Donnerstag, 15. Mai 2008 22:07
To: [hidden email]
Subject: Nipkow Disk Pinholes question

Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

 Hi Folks,

I am wondering if the pinhole-aperture diameter in the Nipkow disk can
be changed in instances where one might wish to open the aperture to
trade away some z-resolution in exchange for increased signal?  I
imagine this could be done by switching between disks with different
sized pinholes, but am not sure if this would be fast and easy enough
such that one could go "back and forth" during e.g. a physiological
experiment.  This seems an area where traditional point- scanning
confocals may have an advantage.

Also, are there different disks for different magnification objectives?
Is the right disk automatically selected on such instruments?

thanks for any info.

Don O'Malley
Northeastern University