As a follow-up to the discussion on Cooled CCD cameras, we have a
Photometrics Quantix camera with a grade 1 CCD chip which
was recently purchased for calcium imaging and live cell time lapse
imaging.
   We have run into the same problem from Photometrics as Jeff Reece has
with the Princeton camera concerning the reduced intensity(20 ADU units
lower than the adjacent columns) on 5 vertical columns. Since there is a
reduced signal instead of no signal, it is not considered a column defect.
We have also been told that it fits within specifications of the CCD chip.
I was told that had there been a note on the production crew  concerning
what the camera was to be used for that the chip could have been more
carefully screened. I thought we had done this as Scott Sternberg of
Photometrics knew how we plan to use the camera  and should have made a
note for the production group. I'm still awaiting his reply.
   I have been told to use a background subtraction as a method of
correction. It is inconvenient and shouldn't be necessary based on the
cost of the camera. Unfortunately, I think this what we have do.
   When purchasing a camera, I would check the specifications for the CCD
chip very carefully.

Patty Jansma                                    Tel:520-621-6671
[log in to unmask]
Arizona Research Labs Division of Neurobiology
University of Arizona

On Wed, 3 Jun 1998, Reece.Jeffrey wrote:

> We have the Princeton PentaMax that we bought primarily for calcium ratio
> imaging, and for deconvolution as well.  The QE is low compared to what can
> be had today, but it is fast, and has some nice features that MetaMorph
> takes advantage of (pixel binning, multiple capture regions).  Unless you
> absolutely need the speed, I recommend that you go with as high a QE as you
> can get.
>
> Another suggestion that has been made before on this list and I strongly
> second the motion: don't settle for a grade 1 CCD chip.  The Princeton
> PentaMax (that we bought through Universal Imaging) has a grade 1 chip.  The
> chip has a vertical line defect at pixel 309 (out of 512), which is close to
> the middle.  All pixels in that line are dimmer by about 20 gray levels.  In
> practical terms, this is significant.  It means that if I want just a plain
> brightfield image of my cells, I can get a better image with an ordinary
> video camera costing an order of magnitude less.  Both Universal Imaging and
> Princeton reps have told me that the chip falls within specs.  I've
> complained to both companies, because I expect more for a $30k camera.  PI's
> response was, after some pondering, that I have to take it up with UI.  UI
> responds that the data is still there, that the line can be subtracted out
> in software.  True to a large extent, but inconvenient.  If I had known that
> these companies don't expect more from their products, I would have made my
> own chip specifications when I placed the order.
>
>
> Jeff Reece
> Biomedical Engineer
> NIEHS Confocal Microscopy Center
> National Institute of Environmental Health Sciences
> P.O. Box 12233, MD F2-02
> Research Triangle, NC  27709
> ph: (919) 541-0311
> fax: (919) 541-1898
> [log in to unmask]
>
>
>
> > ----------
> > From:         Jose' A. Feijo'[SMTP:[log in to unmask]]
> > Reply To:     Confocal Microscopy List
> > Sent:         Wednesday, June 03, 1998 8:57 AM
> > To:   [log in to unmask]
> > Subject:      Cooled-CCD for ion ratio
> >
> > Dear all:
> > This is not strictly confocal microscopy but I thought I could get some
> > input from the list experience.
> >
> > we're conducting a search towards the acquisition of a top-quality cooled
> > CCD
> > for purposes of ion ratio-imaging. We sort of narrowed the choice between
> > Photonics, Photometrics and Hamamatsu. As everybody we have money
> > limitations,
> > but we would definitly like to invest on a top camera and eventually buy
> > the
> > other parts as possible.
> > Therefore we would like to hear comments, suggestions and any usefull
> > information on this subject.
> > thanks a lot for any info
> > Jose
> >
> >
> >
> >
> > ooooooooooooooooooooooooooooooooooooooooooooooooooooooo
> > o                                                     o
> > o Jose' A. Feijo', Prof.                                      o
> > o                                                     o
> > o Dep. Biologia Vegetal, Fac.Ciencias Univ. Lisboa    o
> > o Campo Grande, Ed.C2, P-1700 LISBOA, PORTUGAL        o
> > o                                                     o
> > o tel. +351.1.7500069, fax +351.1.7500048             o
> > o e.mail: [log in to unmask]                         o
> > o URL: www.fc.ul.pt/departs/biologia_vegetal/ejf.html o
> > o                                                     o
> > ooooooooooooooooooooooooooooooooooooooooooooooooooooooo
> >
>