Photographing fog is trickier than you think. Fog produces a unique lighting situation and there are some key things to know before capturing it. I touched on the benefits of photographing fog. Fog is a unique lighting situation that can be trickier to photograph than you might think. Here, I’ll lay out how to photograph fog. These are the important things to know about fog to help make your landscapes eerie, ethereal, and eye-catching.
What is Fog?
In its simplest form, fog is a cloud that sits on the ground. In more scientific terms, it is condensing atmospheric water vapor created by a temperature drop when relative humidity is fairly high. The dew point temperature is a key factor to how fog forms.
The dew point temperature is the point at which atmospheric moisture begins to condensate into larger water droplets. The more dramatic the cool-down in relation to the relative atmospheric humidity, the larger the water droplets become and, consequently, the denser the fog layer.
Fog and Temperature
Have you noticed that we rarely see fog in summer? That is because our low temperatures typically stay higher than the dew point temperature in addition to having less humidity in the atmosphere. This is at least the case here in Western U.S. – in more coastal environments you can get fog any time of year.
Have you noticed how we see fog more frequently in the spring and fall? These two seasons typically have warmer days followed by more dramatic cool-downs at night with typically more moisture. At times these dramatic cool-downs reach the dew point and – boom – we have fog. So as photographers, knowing this provides us with a timeframe to find fog: night and early mornings before the temperatures again rise above the dew point.