Ted,

   Thanks for your input on the Ultraview-- it made me realize a
limitation pertaining to my work.  We can use the "zoom" function on
our BioRad 600 to target all of the laser's energy into the center
of a nerve cell, to selectively photoablate or kill it, while sparing
neighboring nerve cells (for an example of this approach, see the abstract
by Liu & Fetcho at Soc. Neuroscience; abs #654.8).  The Ultraview and
other non-pointscanning confocals would not seem to support this or
related types of experiments, such as local photobleaching.

   I'm not sure I understand the significance of mating a specific
objective to a "pinhole size".  With point-scanning confocals, we
use a variety of objectives and change the pinhole size to obtain an
optimum trade-off between signal intensity and degree of optical
sectioning.  The optical sectioning will of course vary as a function
of lens N.A., immersion/specimen media and optical characteristics
of the specimen.  But I wasn't aware, that for a given pinhole size,
one specific objective would be preferred over others.  Would this be
a substantial effect? (i.e. if I do all water-immersion work and if
the Ultraview is tailored for an oil-immersion lens, is that going to
significantly degrade performance?)

Thanks for any comments,
Don O'Malley
Northeastern University