Update on vaseline experiment.
After a night of heavy rain, followed by a cold morning - no condensation - have I cracked it ?
Before sealing the rubber with petroleum jelly, I dried out the moisture with a hairdrier (set to cold), and allowed the temperature inside the lens to equalise before putting the cover on. They were so wet before, that it took 30 minutes of blasting the hairdrier to dry them out !
After a night of heavy rain, followed by a cold morning - no condensation - have I cracked it ?
Before sealing the rubber with petroleum jelly, I dried out the moisture with a hairdrier (set to cold), and allowed the temperature inside the lens to equalise before putting the cover on. They were so wet before, that it took 30 minutes of blasting the hairdrier to dry them out !