Re: photons vs. photoelectrons?

Posted by Stephen Cody-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Precisely-driving-several-devices-from-IgorPro-through-National-Instruments-board-possible-tp4907273p4928573.html

Dear Mark et al,

As I understand from the promotional material for this camera, there
is a dark calibration procedure built into the camera. The eVolve web
site while very glittzy is quite informative (if you can stand the
hype)

Stephen Cody

On Saturday, April 17, 2010, Mark Cannell <[hidden email]> wrote:

> Hi All
>
> I must admit to being unimpressed by this 'improvement'. It removes (from the researcher) the need to understand what a camera really does and I doubt that it is accurate. Before someone howls at this, I would point out that astronomers who routinely produce calibrated images use a dark and a flat frame to achieve this. Without a dark, you cannot calibrate the camera image -even if you assume it is flat (which it isn't). The problem is that the camera changes it's properties (especially the EM register) so no single calibration is going to be accurate. Since it is easy to actually use darks and flats to calculate actual photon numbers, why rely on a manufacturer calibration? I suggest it's a bit like assuming your Gilson/Eppendorf is still correct and everyone knows that's not GLP -right? But let's be clear, most people don't give a damn about how many photoelectrons there are -they just want a pretty image. For the few cases where photo-electron numbers are needed, the time taken to take darks and flats are trivial compared to the time taken in precise experiments.
>
> my 2c
>
> Mark Cannell
>
>
>
>
>
> *Van:* Confocal Microscopy List [mailto:[hidden email]] *Namens *John Oreopoulos
> *Verzonden:* vrijdag 16 april 2010 16:04
> *Aan:* [hidden email]
> *Onderwerp:* photons vs. photoelectrons?
>
> The recent release of the Photometrics EMCCD "eVolve" camera which has the ability to output images with pixel values that correspond to photoelectron counts......

--
Stephen H. Cody