"Pete Lawrence" wrote in message
...
On Tue, 23 Aug 2005 11:53:09 +0100, "Robin Leadbeater"
wrote:

Hi Pete,

According to
http://groups.yahoo.com/group/DeepSp...ed/message/868
the well depth of an ICX454AL as used in the DSI Pro is 60k electrons
and a
similar figure is given there for the ICX405AK which is claimed to be
similar to the ICX404AK
http://groups.yahoo.com/group/DeepSp...ed/message/427
Don't know about the ATIK2C, but for a given chip design, well depth
tends
to scale with pixel area which would make it about 45k electrons? but
you
could try asking on
http://groups.yahoo.com/group/atik_instruments

Thanks Robin. Unfortunately, I need an official source for this
information. Sony publish the technical specs of their CCDs e.g.
http://products.sel.sony.com/semi/PDF/ICX404AK.pdf but I'm probably
too stupid to be able to determine the value from the data presented.
Either that or it's not shown ;-)
It's not shown.
Remember these are all ABG cameras, so the well capacity should never
normally be reached. Also that 'well depth' figures published for cameras,
are very innacurate. Generally they are 'minima', and for example, it is
common on the some Kodak CCDs, to have the well capacity over 25% higher
than the quoted figure.
You can calculate the gain of the system fairly easily from a group of
different exposure length flat field images, and given this, you can find
either the point where the ABG limits further gain, or if you disable the
ABG, the well depth of the camera. This is what the people who have posted
figures have done, and these are usually nearly as accurate as published
figures, (but reflect the particular example used, rather than the 'worst
case', normally used by manufacturers figures).

Best Wishes