|
Thought it may be of interest how the lens temperature is monitored. These thermistor temperature indicators are the sort used in PC's to indicate temps.
These use 5V and I just mounted them using velcro. The thermistor on the lens is covered by a bit of polystyrene again held with velcro so it measures the lens body temperature at it's thickest part the other measures ambient air temperature.
It turns out by coincidence that for every degree drop in temperature of the lens the focus needs to be moved by 1000 steps. I have found this so far to be linear from 1 to 12 degrees C.
Bert
|