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Nuno Moreno wrote:
> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
> 
> Hi!
> 
> If it is for cell imaging you might consider a BT camera.
> 
> Forcing the previous point, which I thing is very important:
> 
> I'm having the same problem with an ORCA AG with ImagePro Plus.  What I 
> have now is a small program called by macros that controls an external 
> shutter via TTL, which makes a delay till it opens the shutter. I found 
> out that the driver takes almost 500ms to get the camera taking a 
> picture which is unacceptable! However this solution is far from being 
> elegant and sometimes the pseudo synchronization fails! Is this a 
> Hamamatsu problem? With a Hamamatsu BT1024 which has a QE>90% it 
> happends the same thing with metamorph.
> 
> Regarding to the previous commercial response, does anyone have a 
> cheaper and more flexible solution?
> 

The way to do this is by directly controlling the shutter from the chip-exposure 
line of the camera. This bypasses the software completely. Most high end cameras 
  have such a control line, although it goes by various names. I know that the 
PCO sensicam series, Roper Coolsnap series, Orca AG (probably the other Orcas 
also),  QImaging, all have such a line. I use it with a Uniblitz shutter. You 
still have to worry about the the 5-10ms shutter opening and closing time. In a 
camera like the PCO (again, probably in others)  the camera can be set up to 
start integrating after a delay time set by the user. This increases your sample 
exposure by 10-20ms, but that is really not bad compared to the 1-2 seconds that 
some software controlled systems waste before closing the shutter.

Of course, if you connect the control line directly to a system like CoolLed or 
an AOTF, you can get very fast switching.

You may need to build a little bit of digital logic. For example, when doing a 
live preview for focusing, we want the shutter to remain open continuously. But 
when using the chip expose line, the shutter will cycle rapidly as the camera 
switches between integration and image transfer. Therefore, we set it up so that 
in live preview mode the Uniblitz system was commanded to stay open independent 
of the hardware control line. I also added an external switch that could force 
the input to the Uniblitz control to be on (ie, I OR'ed the camera control line 
with a manually switched voltage). This was a matter of a few NAND gates on two 
74LSxx series integrated circuits (your electronics shop will certainly have 
these).

I know that this solution is used in other labs, so maybe I am missing something 
in this thread about the difficulty that is being discussed.

--aryeh
-- 
Aryeh Weiss
School of Engineering
Bar Ilan University
Ramat Gan 52900 Israel

Ph:  972-3-5317638
FAX: 972-3-7384050