What makes lens of a binocular foggy?

Question

What makes lens of a binocular foggy?

Answer 1

Fog!

Answer 2

dunno 'bout binoculars, but me telescope goes a bit foggy an' a blurry at about half a litre o' rum!

Answer 3

Age!

Answer 4

Condensation -- because the lens is colder than the dew-point of the surrounding air so, water vapor condenses out onto the lens.  It doesn't matter if the water vapor is on the inside, or outside of the lens.

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Answer 5

Moisture in the air if on the out side. Ingress of water if on the inside.  Extreme fluctuations in temperature can also cause fogging.

Answer 6

Usually this is caused by moisture getting trapped inside the binocular. The lens itself could also be damaged by improper cleaning.

Answer 7

surprisingly, it is the composition of the gas within the binoculars that creates the fog.  There are fog free binoculars that you can buy.  They come in two varieties. The first has an all nitrogen gas within the binoculars which prevents the fog from forming.  The second has an all argon gas within the binoculars which prevents the fog from forming.   Fog forming within binoculars is not a common occurance but can happen in very humid environments like rain forests or when the humidity is very high and the temperature drops suddenly.  One way to de fog binos is to place them in the oven with the door open and turn on the heat very very low.  The high temperature will de fog the binos.

Answer 8

1- work in Sunny hot day.

2- if you change your pleas from cold please to a hot one ..

tray to take time after changing please  to make sure all vapor is gone before using it