I've got a chest mount for my camera (sony hdr-as15, if it's important). I went on a race last Sunday - it was like +15-17 Celsius. After about an hour of riding I've noticed that the case is all foggy and the picture turned from this enter image description here into this: enter image description here

So, what can be done to prevent this?

  • 1
    Was the fog inside or outside the camera housing? If outisde it's probably getting sprayed up off the ground, or from riding through mist/low cloud. A rinse would help (assumign the camera is waterproof)
    – Chris H
    Commented Sep 11, 2018 at 13:48
  • @ChrisH - from the inside. I mean between the camera and it's case
    – k102
    Commented Sep 11, 2018 at 14:21
  • 3
    Then I suggest either the case wasn't sealed, or was sealed with moisture inside and your body heat evaporated that moisture, which then condensed at the coolest part. I've seen that with a camera in a waterproof case used for kayaking, when it got damp inside the case one day and fogged up the next
    – Chris H
    Commented Sep 11, 2018 at 14:24
  • 1
    you could also ask on photo or video stack-exchange channels.
    – Max
    Commented Sep 12, 2018 at 14:32

2 Answers 2


Normally I would not expect this at 15C-17C, its something that happens at 5C.

Presuming the case is sealed and was dry before closing it up, the cause is because the inside of the case was warm with high humidity before being taken into colder air. Most likely the warm air inside your home is damp, or the case has been sealed up for a while. When taken outside, the air in the case cooled, and was no longer able to hold the water vapour so it condensed on the coldest part - the lens that points away from you as that gets no body heat.

To prevent this, leave the camera case open when in storage, and store in a dry location (stuffed in you gear bag with your damp cloths and shoes form the last ride is really not a good idea). If the temperature changes is high - e.g when I head out on 0C degree morning, I leave the camera and case open in cold outside air before sealing it up for the ride, ideally for at least an hour.

An alternate, if conditions are suitable, is to use a non-waterproof case that has massive slots to allow airflow.

  • 1
    A bag of rice is what scuba divers and others use to desiccate their camera equipment before going under.
    – RoboKaren
    Commented Sep 11, 2018 at 22:45
  • 2
    There are those little silica-gel bags that come in the packaging of some equipment. They can even be re-used after they have been heated to release the absorbed water.
    – Carel
    Commented Sep 12, 2018 at 9:26

Go-pro cases are notoriously lacking in spare space for rice or silica gel sachets.

So Gopro themselves make an "anti-fog insert" which is labelled as a "HUMONITOR"

Details are at https://shop.gopro.com/APAC/accessories-2/anti-fog-inserts/AHDAF-302.html but they look like a lot thinner than a silica sack and can fit between the camera and the housing.

Downside, they're not cheap.

  • 1
    Had a quick search on google, it looks possible to buy desiccant paper a lot cheaper than the branded product.
    – mattnz
    Commented Sep 12, 2018 at 23:10

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