ATM Re: CCD sensitivity

[Al Kelly <akelly@ghgcorp.com>]

Apparently there is also a speed gain in using hypered film in
>exposures < 1 sec. The ''figures'' that I have seen (I think in the
>Lumicon literature but don't quote me) is about 2x. But it is not
>clear to me if you can use this information to extrapolate the above
>from 2 photons to 4 photons?? Would you mind sharing your sources for
>this information?

Chuck,
        I would be glad to if I knew them all!  The photon efficiency figure
I stated for CCDs (50%) is an approximate average based on data that I have
read over the years in a number of places....articles in CCD Astronomy,
Christian Buil's book, and the CCD Camera Cookbook, to name a few sources.
The average figure I stated for unhypered film (2%) is also a datum that I
have seen in many print sources over the years.  I have read the same thing
you have about the somewhat increased efficiency of hypered and chilled
emulsions.  Perhaps someone else on the list can address this in detail.

Al Kelly