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With summertime comes hot and muggy conditions in many parts of the world, which as you may have experienced tend to cause foggy lenses, viewfinders, and camera screens when bringing your gear from cooler air conditioned buildings into the outdoors. You may be wondering why this happens and how to keep your camera lens from fogging, especially if you’re traveling and don’t want the hassle of waiting for the fog to clear.
The reason this occurs is due to condensation, which happens when your camera and camera lens is cooler than the dew point – the temperature at which the humidity in the air condenses into actual droplets of water. A higher dew point means there is more humidity in the air, so if the room you’re in cools your camera down to 65 °F, but the dew point outside is 70 °F, the moisture in the air will condense and form dew when you go outside, fogging your camera lens with tiny water droplets. You may have found that even when you wipe the fogged lens with a cloth, it quickly fogs up again. Since camera lenses are comprised of several glass elements and many lenses and camera bodies are not completely sealed, the warm, humid air is often able to penetrate inside of your lens and camera body as well, forming foggy condensation on the cooler surfaces that you can’t easily wipe off.
Not only is this an impediment to photography, but repeat exposure to internal condensation can potentially damage the sensitive electronics that make the camera and lens function. Weather resistant cameras like the Sony Alpha a7R V, Nikon Z8, Canon EOS R6 Mark II, Fujifilm X-T5 offer additional sealing and protection to the internal parts of the camera when used with a weather resistant lens, but even these more ruggedly designed cameras and lenses will still fog on the outside surfaces like the front lens element when their temperature is cooler than the dew point, making it advisable to prevent condensation from occurring no matter what kind of camera you’re using. Once your camera lens fogs up, it’s going to take quite a while for the condensation to stop forming even if you keep clearing it off. It’s best to prevent fogged lenses to begin with!
Besides just hanging out in the cool comfort of an air conditioned room all day, there are some easy steps you can take to avoid the annoyance of fogged up lenses and condensation on and in your camera.
- Keep your camera with the lens attached inside of a sealed plastic zip-top bag. By sealing your camera inside a bag, you’re allowing it to slowly warm up to the outside air temperature, while preventing condensation by keeping it surrounded with the drier air from inside. How long you’ll need to keep the camera inside of the bag depends on the temperature of your gear and what the dew-point is. If the temperature inside the building or car you’re coming from is only a little cooler than the outside air, you might only need 10 or 15 minutes before you’ll be ready to take it out of the bag.
- If you know you’ll be heading outdoors to take photos, try to keep your camera in a warmer place like a zipped-up camera bag rather than on an open table or shelf where it will quickly cool from air conditioning. The closer your camera already is to the outside ambient air temperature, the shorter the time it will take to acclimate inside of a sealed bag to avoid condensation.
- Avoid changing lenses shortly after coming outside. Even after the front element of your lens and the outside of your camera has acclimated to the warmer ambient outdoor temperature, don’t remove your lens for at least some time, because the internal surfaces of your camera and the glass elements deeper inside your lens may not have warmed up to the outside air temperature yet.
- If your lens does fog outside in the humid air, don’t worry and start trying to wipe away the condensation — just be patient. Even though it’s better to avoid letting the condensation form to begin with, it will evaporate as the lens warms up. This might take more than 15 minutes if the temperature difference between your camera lens and the ambient air is especially extreme.
Enjoyed these tips? Check out this comprehensive tutorial for more tips on photography in wet, rainy, and humid environments. Condensation isn’t just a warm weather phenomenon; it can happen in the cold too – here’s our guide for preventing foggy lenses in cold weather.