Cameras, Humidity and Condensation

by Tony Drew

You will often find posts about protecting your camera and equipment from condensation or humidity, but most are about storing and transporting your equipmentⁱ. It’s more important to know how to operate in these environments and when to expect problems. It’s also not just the tropics you need to worry about; cold climates can also be a problem.

The following has been simplified to make the subject easy to understand so any Mechanical Engineers reading this, please take this into consideration.

The Problem

When in the tropics, how many times have you walked out of your lovely air-conditioned hotel and attempted to take a photo, only to find that the lens and eyepiece of your camera are both covered with condensation? Alternatively, you have spent the day taking photos in the snow. When you get back to your lovely warm hotel, exactly the same thing occurs. If you are anything like me, two or three times a trip and I know better.

This problem is in fact related to both Temperature and Humidity and you need to understand how these two interact. So for those of us without a Degree in Mechanical Engineering, there is one simple parameter that will make this subject clear. This is something called Dew Point Temperature.

Dew Point Temperature is provided by every weather service, so look for it. If you have a smart phoneⁱⁱ there are many iPhone and Android weather service applications like AccuWeather, WeatherBug that can provide this data for you, in close to real time.

Dew Point Temperature is the temperature at which the humidity (or water Vapor) in the air will condense (become a liquid again). What happens when you move from one environment to another is that the camera temperature was at or below the Dew Point Temperature. This caused the water vapor in the air to condense on any cold objects like your camera.

Say the Hotel air Temperature is 22°C (72°F), outside air Temperature is 33°C (91°F) and the Dew Point Temperature is 24°C (75°F). In this example any object at or below 24oC (75oF) will cause condensation to form on its surfaces (fog on the lens). Alternatively, if the outside air temperature is -6°C (21°F) and the temperate inside your hotel is 18°C (64°F) and the dew point is 1°C (34°F), again condensation will form on your equipment.

In Tropical Environments

All air-conditioned spaces, Hotels, Offices, Cars, ships and Planes are not humidified (humidifiers use lots of power and need lots of water). In fact the cooling process will dehumidify the air, meaning that the air is relatively dry. This will produce a very low Dew Point Temperature. So once you are in an air-conditioned space, the chances of condensation forming are nonexistent.

In Cold Environments

Some hotels and offices have humidifiers but all other environments do not. In most cases the heating process will also dehumidify the air. There is a small chance that condensation can form on your equipment, if you are not careful. Also in these environments, the Dew Point Temperature you need to know is not outside, but inside your hotel, not something that’s available from a weather service.

At the time of writing

Temperature in Bali (Indonesia) is 31°C (89°F) and partly cloudy
Dew Point Temperature 22°C (72°F)

In the above example I would expect to have a problem with condensation because 22°C (72°F) is a fairly high temperature and some hotels run their cooling systems down to 18°C (64°F).

Temperature in Melbourne (Australia) is 13°C (55°F) clear sunny day but was below freezing overnight in the hills
Dew Point Temperature 3°C (37°F)

In this example you may think that you wouldn’t have any problems, because the Dew Point Temperature is so low, 3°C (37°F). If you leave the equipment in the car overnight and the temperature went down below freezing so your equipment will be very cold. You will need to make sure it’s warm first or condensation will form.

Temperature in Ha Noi (Vietnam) is 29°C (84°F) and overcast
Dew Point Temperature 28°C (82°F)

This will not be a very happy time to use your camera. You will need your camera temperature to be at least 29°C (84°F), which is fairly warm. There is also so much humidity in the air that all of your shots will be poor, so leave your camera in the bag. For those of you who have not experienced trying to shot in these conditions, I can best describe it as blur, everything looks out of focusⁱⁱⁱ.

Prevention

To prevent condensation from occurring:

1. Know what the Current Dew Point Temperature is before setting out.
2. Keep the temperature of your equipment above the Dew Point Temperature (keep it warm).

Things you can do:

• If you have a P&S, keep it against your body i.e. on a lanyard around your neck and inside your top.
• If you have a DSLR you may attract some strange looks if you have your camera stuffed down your shirt (don’t try this going through customs). What I do is as soon as I can get the camera out of the bag and let it warm up before removing the lens cap. The time required will depend on the size (mass) of your lens but I would typically wait 2 hours. Any direct sunlight will help it warm faster. As soon as your lens is no longer cool to the touch you will be fairly safe.
• In tropical climates, store your equipment in a un-air conditioned room at the hotel like the bathroom and keep any doors to air-conditioned areas closed.
• In tropical climates, make sure that you keep your car air-con temperature set as high as comfortably possible.
• In tropical climates, use your camera bag like a blanket to keep your equipment warm by putting it away before going into cool areas.
• In cold climates, keep you equipment in a warm room; never leave it in a car if you can.
• In cold climates, if you have been out in the cold for some time, put your camera and lenses in re-sealable plastic bags. When you enter a warm area the condensation will form on the outside of the bag, not on your equipment. Once the equipment has acclimatized^iv you can removed that from the bags and pack them away.

Summary

It doesn’t matter if you are in the Tropics or the Arctic, what’s important is the Current Temperature, Dew Point Temperature and the temperature of your equipment.

Or, happiness is a Warm Body.

Tony Drew, Tony4d2@gmail.com

 
If you have any comments or suggestions regarding this post please feel free to contact me.

ⁱ You can store and transport your equipment by placing it in plastic bags with some form of Desiccant.

ⁱⁱ If you are traveling overseas be careful of the Global Roaming Data Charges, they can be a shock when you get home. In my case, roaming data charges are 100 times my local charges.

ⁱⁱⁱ When you are in a desert and you see heat haze, such atmospherics can make an interesting shot. Unfortunately, when it comes to a very humid environment I have never seen a shot worth keeping.

^iv Unfortunately, by placing your equipment is resealable plastic bags, you will also be adding an extra thermal insulator. This means it will take considerably longer for your equipment to acclimatize.