The reality is going back to the Op's question is any CCD sensor will create noise when it gets hot or very warm. The question is when does that happen.
Hi Guy,
It's not really a "when" does it happen question. CCD sensors typically double their so-called
dark count for each six degrees Celsius (or Kelvin) increase in temperature. So there
will be noise, especially with increased temperature.
Whether it will be noticeable depends on how much noise there is (which varies between sensor designs), but also in relation to the actual signal (the exposure) level (hence my earlier remark about the almost 2 stops 'underexposure' for the ISO value). As the above link says, "
Having lower dark count is always desirable, but there comes a point when other factors such as shot noise or S/N supercede dark count considerations".
So there are 2 factors that matter, CCD sensor temperature controlled by cooling, and the absolute amount of dark count during the 'exposure' time versus the actual exposure level.
Cheers,
Bart