Gain: e-/ADU v dB? Please explain.

[[1ponders] (Paul)]

Hello CCD camera gurus.

Is there a relationship between gain expressed as electons/ADU and the gain in dB. Eg. If I look at the specs for the Canon 300D it has a gain of 2.41 e-/ADU @ ISO400, but the DMK21AF04.AS has a gain of 0-36 dB.

Thanks

[jase (Jason)]

If I'm not mistaken, both units represent the camera dynamic range. As you are probably aware, the dynamic range is the ratio of the maximum useable ADU count to the read noise. If the ratio the can be presented as decibel scale or as a power of 2 ('bits'). For example, a system with a well depth of 100,000 electrons and a readout noise of 12 electrons would have a dynamic range = 10 log 100,000/12, i.e. 39 dB or ~13 bits.

[[1ponders] (Paul)]

Fantastic, just what I am looking for. Your are right, it does have to do with the dynamic range but I just couldn't put the two together. Thanks Jase