I noticed that focus did not change as much with temperature when using the fridge. I also had a dew heater around the base of the lens to stop the filter at the rear of the lens getting condensation. I took this a step further and heated the whole lens with two 10 inch Kendrick heater straps and used a thermostat to keep the temperature relatively constant. Focus does not change at all. I focused last night once everything was at equilibrium and ambient was 17C. This morning it was 2C and focus was still perfect. I will write this up and put it up in DYI.
Lagoon and Trifid 4MB
http://d1355990.i49.quadrahosting.co...05/lagtrth.jpg
Bert