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

 
We use an extra magnification in front of the EMCCD camera with 2 achromat
lenses. The first one has f=150mm and the second one f=300mm, giving 2x
magnification (the real microscope image is in the back focal plane of the
first lens). In combination with an 100x NA1.4 objective lens this gives us
90nm per pix (16µm pixels), in good agreement with the Nyquist criterium. In
stead of the second lens, one could use a zoom lens with adjustable focal
distance (e.g. 300 to 500 mm) so that the magnification can be increased
when using binning on the camera.

Clearly this approach means that you have to detach the camera from the
microscope and position it at a distance on the optical table. The upside is
that the infinity space in between the lenses can be used to add components,
such as emission filters, notch filters or a dichroic to split up the signal
in 2 spectral channels.

If you don't need the infinity space, you could make the setup more compact
by using shorter focal length lenses.

Best regards,

Kevin


Kevin Braeckmans, Ph.D.
Lab. General Biochemistry & Physical Pharmacy
Ghent University 
Harelbekestraat 72 
9000 Ghent Belgium
Tel: +32 (0)9 264.80.78
Fax: +32 (0)9 264.81.89
E-mail: [log in to unmask]

> -----Oorspronkelijk bericht-----
> Van: Confocal Microscopy List 
> [mailto:[log in to unmask]] Namens Vitaly Boyko
> Verzonden: donderdag 28 september 2006 20:11
> Aan: [log in to unmask]
> Onderwerp: image undersampling
> 
> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
> 
> Dear List,
> 
> Does anyone knows how to deal with image undersampling with 
> new generation of EM-CCD cameras with16 um chip pixels (these 
> come with an option for 2x2, or even 4x4 binning - what an 
> attractive thing!).
> 
> Are there smarter ways to break the laws of nature than 
> increasing the magnification (150x) and reducing N.A. to 1.3 
> or less (losing  "precious" 
> light), "liking mCherry, hating GFP" etc?
> 
> Vitaly
> 
> NCI-Frederick,
> 301-846-6575
>