Fog is my favorite element to shoot in: many of my images have been made in foggy conditions. These are 5 things I look for when I run into fog.
#1 Fading into the fog
Lines that fade into the fog are one of the most powerful subjects we can find, in my opinion. They create mysterious images that spark the imagination of the viewer, because they make you think about what might be beyond that fog.
Roads, paths, train tracks, power lines, fences... anything that creates a line that disappears in the fog will do the trick.
#2 Hide and Seek
Sometimes fog partially hides a subjet, showing only a part of it. For example, low clouds might cover the bottom of a mountain, making the top the only visible part. Same thing can happen with tree or buildings.
#3 Subject isolation
I like to call fog the poor photographer's bokeh because of its capacity to isolate subjects from the background, by removing the noise. Subjects usually out of reach due to a very busy background might become perfect on a foggy day, when the fog hides all the noise around them.
#4 Atmosphere
Fog creates a unique atmosphere, sometimes otherworldly. It's a good opportunity to place a person, animal or object in those landscapes that seem to belong to another planet.
Other examples are lights at night that reflect on the fog and beams of light through forests.
#5 Above the clouds
If you can, get to higher grounds. You might run into something called a cloud inversion where clouds cover the whole landscape below you. Depending on the location, this event ranges from rare to extremely rare and it has the potential for extraordinary images. Look for tall objects that make it through the fog, like buildings, hills or power lines.