Hi Max,
Well, a good idea, but only a theroretical consideration invalidated this unproven thesis :
the "aperture time" of bias were as short as possible, and temperaturfluctuation ( better voltagefluctuation ) in this short time,
is excluded. the whole bias-session as well.
but : the effect is , indeed , voltage-dependent, howsoever.
I will test grownding of the powersupply and the cam, today.
thanks a lot
Gerhard