Housing fog
Also known as: lens fogging, camera condensation, GoPro fogging
Condensation that forms inside a camera or its housing when warm, humid air meets a cold lens, turning footage milky and hazy until it clears.
Updated
What it means
Housing fog is moisture condensing on the inside of a lens cover or waterproof housing. Air sealed inside holds water vapor; when the front glass gets colder than that air can tolerate - plunging into cold water, riding a chairlift in sub-zero wind - the vapor turns into a fine mist of tiny droplets on the glass.
It shows up as a milky haze, often starting at the edges and creeping toward the center, with flat contrast and glowing highlights. Unlike drops on the outside, it cannot be wiped off on the slope or in the water, so it can ruin a whole run of ski or dive footage.
How it works in practice
Prevention is about dry air and stable temperature. Close the battery door or dive housing in a cool, dry room, not in a steamy bathroom or a warm car. Drop anti-fog inserts into the housing to absorb moisture, and dry them out between uses. Let the camera adjust to outside temperature before you start recording.
For skiing and snowboarding, keep the camera outside your jacket rather than warming it against your body and then exposing it to the cold. Heat from the camera itself adds to the problem: recording 4K at high frame rates warms the air inside, which then condenses on the cold front glass. On a helmet mount the wind keeps that glass cold, so dry air inside matters most.
What to watch out for
Opening the housing or battery door outdoors in cold, damp weather to swap a battery lets humid air in, and the next clip fogs. Swap batteries indoors or inside a dry bag where possible, and brush off snow before opening anything.
Fog can look like soft focus or a dirty lens cover, so check the inside before blaming the camera. Do not expect to rescue it in post: dehaze and contrast adjustments recover only a little, and a fogged clip never looks clean. Fog usually clears once inside and outside temperatures even out, so pause rather than keep shooting through it.
How RawClip handles it
RawClip does not remove fog, so prevention before you shoot is the only fix. If a few clips are badly fogged, leave them out of the upload; send the rest of the session and the AI picks the strongest runs, jumps and moments for your highlight.