Whether you are shooting a narrative project, a music video or just an event like a wedding or DJing a party, fog and haze machines are great tools to achieve more depth in your scene, to diffuse the light or just create a certain atmosphere. If you are wondering whether you should go for a fog machine or a haze machine, here are some considerations you should look into:
Fog machines use a “fog fluid” which is a mixture of glycol and water, which is heated until it vapourizes through a heat exchanger, creating a thick fog effect. Fog created by fog machines, even if dense, don’t last long and rises fast. A technique used to avoid the fast rise and dispersion of the fog is to “chill” the fog coming out of the fog machine either through a container filled with ice or other devices.
Things you might want to consider before using a fog machine is that fog machines require a warm up time, on average about 5 minutes, and go through a “reheat” cycle every time they are used as they need to pause to reheat in order to produce fog again. This doesn’t apply to all fog machines but generally the cheaper ones, with a lower wattage (up to 1200-1300W). More advanced fog machines equipped with a higher wattage won’t need to re-heat.
In general, fog machines get the results faster (once heated), produce a fog effect that is thicker than haze but also has a stronger odor so it’s something to consider if you are using it in a wedding or an event where people can be sensitive to that.
Hazers, instead of vaporizing fluid, use a compression chamber with an air compressor that ejects the vapor using a fan. The result is a more uniform, thin, “mist-like” fog effect. Is more recommended for events where you need to accentuate a specific lighting effect.
There’s no warm up time for haze machines and will work right after you turn them on. It is also odorless and will hang on for a longer time. Finally, it will be less likely to trigger fire alarms.
Even if there’s no long term health hazards from the use of glycol based fog or haze machines, make sure to inform whoever is on set or at the event where you will be using them. Short term effects may include dizziness and headaches and respiratory problems for people that suffer of asthma.
So to summarize:
Fog machines produce a thick, dense fog effect that disperses quickly and they need time to warm up before use
Haze machines create a thin, mist like fog effect that hangs on the air for a long time and they don’t require any warm up time
Fog and haze machines are relatively cheap to buy or rent and can add a lot to your project or event as they can be used to achieve several different goals, from just a pure atmospheric smoke effect to just accentuate depth or create cool lighting effects.