Christian,

I read your comments on the Leica & Zeiss systems since we (a small group studying Ca & pH) are about to purchase a confocal and oscillate between the two companies. 

Can you tell me how rapidly you can linescan with the Zeiss: on paper the Leica can scan slightly faster, although with non-excitable cells we may need a video rate system in order to reliably detect unitary Ca events.

Thanks
Martyn

Dr Martyn Mahaut-Smith
British Heart Foundation Science Lecturer
Department of Physiology
University of Cambridge
Downing Street
Cambridge
CB2 3EG

Tel: 01223 333863
Fax: 01223 333840

-----Original Message-----
From:   Christian Lohr [SMTP:[log in to unmask]]
Sent:   Friday, December 03, 1999 6:26 PM
To:     [log in to unmask]
Subject:        Re: COMPARISON OF CONFOCAL SYSTEMS

Dear Phil,

during a period starting fall 1998 until summer 1999 I had the
opportunity to get extensive demonstrations of and work with different
systems, since we were in the same situation like you. First, we also
have not seen the Biorad (they don't seem to be present at the european
market). We also narrowed it down to Zeiss and Leica. Both of them are
very good systems and well suited for multi-user facilities. I can list
a few major differences I have in mind (there are more for sure).

Hardware:
Optics: The optics of both systems are two of the best on the market.

Confocal system: Leica TCS SP has the filterless spectral emission
optics, which allows to adapt the range of wavelength at the detector to
the emission spectrum of the dye or dye combination used.
Leica has a new scanner for fast scanning. However, last summer (99) the
scanner box was yet not able to control the scanner in a way to provide
this high speed. I don't know what the state is now.

Zeiss has a digital control of the AOTF, which allows very fast changing
between excitation wave lengths of the mounted lasers. One advantage of
this is the multi-track option. One can detect e.g. the FITC channel on
the way of the scanner from one side to the other (without exciting the
second channel, e.g. TRITC), and detect the second channel on the way
back (without exciting the FITC channel). Since never both dyes are
excited simultaneously, there is no bleed through. This can be used even
with more then two channels. Of course, the scan speed is slowed down.

Two-photon: I have no experience with the two-photon options of both of
the systems.

Software:
We are mostly interested in physiology (calcium or pH imaging). With
respect to this, the Zeiss software compared favorable. A very good
option is the random line scan. One can scan a line along e.g. an axon,
including curves. This is limited, because the scanner cannot scan sharp
corners etc.
For morphological studies, I cannot really say which software is better.
The basic features are more or less the same, and one has to check
whether the one or the other systems has options for special needs.


Conclusion: Unless physiology isn't a major interest, both systems are
very good. Thus, I would make the decision by the price, service,
experiences with the company etc.

We (in my 'home lab' in Germany) have bought a Zeiss LSM 510 and had no
trouble yet.
I have no commercial interest in any of the companies.


Best wishes
Christian




--
Christian Lohr, Ph.D.
ARL Division of Neurobiology
University of Arizona
PO Box 210077
Tucson, AZ 85721-0077
Phone: (520) 621-6671
FAX: (520) 621-8282
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