I am convinced the risk of internal fogging of the Retrovids is greatly exaggerated.
I have been using my Retrovids as well as many other non-sealed binoculars, such as the Nikon E II (see pic), for many years in bad weather and have in the last 50 years never experienced internal fogging.
I do not deny that people living in the tropics, the Sahara or in Antarctica have good reason to use sealed and nitrogen-purged binoculars. But for people in moderate climate zones, in my experience non-sealed binoculars rarely pose a problem, even when used in humid conditions.
The biggest issue for me with fogging up is bringing binoculars inside into a heated house from a cold outside environment, and that issue usually only concerns
external fogging up of the lenses. And there is a method to avoid fogging in such an instance.
Fogging up occurs when a surface cooler than the environment is exposed to warmer air that contains sufficient humidity. Stored in the house at 19 degrees C and at humidity levels around 40-60%, my unsealed binos will not fog up internally when brought outside, whether it is cold outside or warm or humid; moreover, the relatively dry air inside the bino will normally only very slowly be replaced with (humid) outside air.
Funnily, I have seen fungus on sealed binos which had a certain age, but so far never on unsealed binos
As I told a forum colleague here on BF recently, I would of course not use a bino that is not fully waterproof and sealed
- on a boat in a storm with waves crushing over the planks
- on a dog-sled in Antarctica at minus 30 degrees
- during a thunderstorm in the rainforest at 96 plus degrees
- during a sand-storm in the Sahara,
but that is sort of common sense, isn't it?
Canip
