>
> 1. The SPOT camera is certainly a very good all-in-one choice.
>

The main problem with the slow scan cameras (like the SPOT) is focussing
with high NA lenses for weak fluorescence. Even though there is a subarray
fast focus mode that can put out a few images per second, it does not help
if the signal must be integrated for a second to get a usable image.
With the color filter in place, the problem is much worse because then
the camera is much less sensitive. Focussing on the brightfield image does
not always help because the fluorescence image may not be exactly at the focus
of the brightfield image (ie, you may focus on a different plane in the
brightfield mode). The SPOT and SPOT Jr do not have slidable color filters,
so they can only be used in the color mode if that is how they were purchased.
The SPOT-2 and I believe also the SPOT-RT can be used with a slidable color
filter that lets the camera operate in either color or mono mode. I truly
do not know why Diagnostic Imaging (makers of the SPOT series) did not
make the SPOT Jr with a slidable color filter.

The DVC-1300c (and I am sure many other cameras with fast outputs) solves
this problem because you can control the gain and offset of the camera
from the computer, and you get a wide range of gain. Therefore, you can
raise the gain to get a noisy image which is fine for focussing, and then
reduce the gain and integrate to get a high quality image.

If one only requires monochrome imaging (which I think is prefered
for fluorescence and other weak signal work), then there are many interesting
options, all of which have fast focus modes that work reasonably well.

--aryeh
Aryeh Weiss                          | email: [log in to unmask]
Department of Electronics            | URL:   http://optics.jct.ac.il/~aryeh
Jerusalem College of Technology      | phone: 972-2-6751146
POB 16031                            | FAX:   972-2-6751275
Jerusalem, Israel                    | ham radio: 4X1PB/KA1PB