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Dear list,
As Ian says, the EMCCD is not meant to produce 'pleasant' -like pleasant
in the sense of cover picture quality- images in the electron
multiplying mode. It is optmised to detect a signal where there is very
little contrast and thereof produce a 'terribly' noisy picture of your
object where you otherwise wouldn't see anything but noise. And of
course it is meant to do that at a rate of several full frames per sec.,
otherwise it is outcompeted by super low cooled slow scan cameras.
One nice, and in my opinion the most important, feature of these cameras
is their flexibility. For example you can focus the sample at max. gain
-and still high enough resolution to see the details you want to focus
on- and later switch to low gain and capture a decently focussed
picture. Or you can take really fast timelapse movies of fast moving
particles to be able and track the particles. Or you scan mosaics of
thausends of images pretty quickly to have a nice overview of a huge
area of your sample at relatively high resolution, relatively quickly.
EMCCDs increase flexibility into the 'fast' and 'low contrast' dimension
of CCD imaging and -as a result of the 'fast'- the 'large volume at
moderate resolution' dimension of your sample, but surely not into the
high resolution dimension. (This is by the way exactly what spinning
disk microscopes do and that's why the two of them combine so nicely.
And these are, by another way, the directions biological research is
expanding into at the moment...)
You may use an optoVar in order to adapt to a high res., though the main
reason to postmagnify for me is to adapt to the sampling criteria
imposed by deconvolution algorithms.
Of course if you can afford to buy a dedicated camera and objective lens
for each and every of your imaging tasks, you may be better off (at
least if you know when to use which camera). If you don't want to buy
many cameras, don't want to switch cameras for every application, and
still cover a broad range of modern bilogical applications, the EMCCD is
the camera to go for.
regards, jens
---
Dr. Jens Rietdorf
Head Microscopy
Novartis Research Foundation
Friedrich-Miescher-Institute, wro1066.2.32
Maulbeerstr.66, CH-4058 Basel, Switzerland
phone +41(61)69-75172 mobil +41 798284737
Email:[log in to unmask]
-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]] On
Behalf Of Ian Dobbie
Sent: Donnerstag, 12. Juli 2007 10:13
To: [log in to unmask]
Subject: Re: AW: Hamamatsu EMCCD
Search the CONFOCAL archive at
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Vitaly Boyko <[log in to unmask]> writes:
> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
> Dear List,
>
> I have mentioned this (below) several times - sorry for boring you up.
>
> I have tested Hamamatsu 16 um pixel EMCCD back in 2004 versus
> Hamamatsu EB-CCD.
>
> I was testing HIV particles labeled with mRFP1 - a Red Fluorescent
> Fluorescent Protein.
>
> To my surprise, the EB-CCD outperformed EM-CCD. By eye I could hardly
> see signal above background, same was true for the EM-CCD, only
> sparklings were seen. EB-CCD was still giving a pleasant image.
This should not surprise anyone. The main advantage of the EMCCD's is
that you can go fast with a very low signal. If speed is not an issue
then a non amplified CCD will give you a better SNR. I suggest anyone
interested in this go and read Jame Pawleys excellent and very detailed
coverage of this issue in the latest edition of the Handbook of
Biological Confocal Microscopy. The relevant section is free on the web,
available at the Springer web site.
Ian
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