Posted by
Julio Vazquez on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Cooling-time-for-CCD-cameras-tp7554139p7557259.html
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Hi Esteban,
not sure why you would need a specimen at all..... I typically check cameras by taking several dark exposures at different exposure times (such as from 10 ms to 1 second) and look at the image histograms. This can be very informative, and will allow you to not only measure or estimate dark current and thermal noise, but will also show dark and hot pixels, and sometimes other funky things. If the camera has different read out modes or gain settings, it is also useful to test those. Taking varing exposures of an actual (ideally homogenous and non-bleaching) sample can give you additionla info, such as how linear the response of the camera (and/or individual pixels) is. We typically do that with fluorescent plexiglas slides.
=
Julio Vazquez
Fred Hutchinson Cancer Research Center
Seattle, WA 98109-1024
http://www.fhcrc.org==
On May 12, 2012, at 2:28 PM, G. Esteban Fernandez wrote:
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> Hi all,
>
> 1) I'm curious how much time, roughly, it takes for a Peltier-cooled
> CCD camera to reach the lowest temperature. Are we talking a few
> minutes or closer to an hour or more? I have several brands of cooled
> CCDs of different vintages and I'm just looking for a "rule of thumb",
> if possible.
>
> 2) I do plan to test my cameras myself: I was thinking of imaging a
> timelapse of a dim & stable specimen (requiring something like 30-60
> sec. exposure) after turning cooling on to see at what time noise
> reaches a minimum. Any suggestions for other ways to test this are
> welcome.
>
> Thanks,
> Esteban