Using Fog and Creating Shafts of Light
A standard tool in movie making is a fog machine. Fog adds atmosphere to a shot, reduces contrast, softens the image and can create shafts of light.
Fog machines are great for shooting night 
exteriors because a few small light units can illuminate a large area when fog is present. The light hits the fog (as in this image with the rocking chair) and that adds an additional lit element to the frame. After all, light needs to hit something for the human eye to see it. Choose a night that isn’t windy as it will sweep your fog away…
For interiors, check that the room you’re shooting in doesn’t have a super-sensitive smoke detector. Use a piece of foam core, grip flag, or some poster board to fan the fog throughout the room for even distribution. Your objective is to build up the level of the fog throughout the room gradually, and let it settle slightly before shooting. It’s often better to have a general haze in the room rather than a lot of smoky swirls.
For shafts of light, use a strong, focused light source and aim it downward through the fog. The shot on the right is from Citizen Kane, a movie famous for epic shafts of light like this.
(info added)
Illuminated atmosphere, such as fog, becomes a whole 
separate light source. The trick is deciding how to expose and light the scene. There are lots of different ways to illuminate fog. An unfocused light source, such as an openfaced light, a flood light or other utility light will make the light bounce all over the place. This is a good way to create glow and bring up the overall light levels in the room.
For shafts of light, you need a focused light source, such as spot light, fresnel light (a light with a lens on it which focuses the light into a beam), Xenon light, theater lights, or even halogen lights.
Many people buy fog machines for Halloween parties, and then they go on sale round about November 1st. That’s also a good 
time to check out eBay for bargains. You’ll also need to buy a bottle or two of “fog juice,” the stuff that makes the fog when pumped into the machine. Fog juice has a very distinctive scent that always makes me think of a zombie movie I worked on once, called the “Bacon Wagon” (no, I’m not kidding). I’m going to keep my eyes peeled for an inexpensive fog machine because I think it can add an extra dimension to my photography.
All of the images I’ve used here are from great films. From top to bottom, these are Road to Perdition, The Village, V for Vendetta, Citizen Kane, Close Encounters of the Third Kind, and Seabiscuit.
Responses and Conversations
I bought a small fog machine a while back but haven’t had the chance to use it yet, hopefully when we get in the new house!
Comment by JimmyD on September 17th, 2006 at 8:11 pm
Thanks for the tip, but what kind of lights are best recommanded? And roughly what is the minimum watt i should use, especially in large inoder space like a church?
Comment by Desharado on August 9th, 2007 at 11:25 am
Well, there are a lot of variables to that question (shooting film, video, stills, shooting something moving or long exposures, etc). In large budget feature films, the most common light used for shafts of light are Xenon Lights.
http://www.arclightefx.com/britelights.htm
PAR lights (tungsten or HMI, depending on the color temp you are shooting) are also a good choice because they have a long throw and a lot of punch for the amount of power they draw (and rental affordability).
For a large lighting environment like a church, you will need at least two fog machines and a lot of time to distribute the fog evenly throughout the building. Fog swirls until it settles in an evenly distributed way) Make sure that level of fog will not set off sprinklers in the space. Outside the church, place one or more lights from a high angle and make sure to match the angle of the other lights so the light looks to be cast from a single bright light source outside.
You will need a generator appropriate to the power levels of the lights you are renting.
Another choice is to rent a movable lighting truck and aim the lamps in through the windows.
If this all sounds way beyond what you were looking to do, try lighting a smaller space with shafts of light, like a chapel. You can also shoot during the day so that the sun shines at the right angle through the windows. The sun will need to be at an angle to shine directly through the windows. Make sure to give yourself enough time to fill the space with smoke before the sun is at the right angle.
I hope this helps.
Cheers,
Stephanie
Comment by Stephanie Simpson on August 9th, 2007 at 12:55 pm
Thanks alot for the help, it’s a matter of time i try it out. Anyway, do have tips for creating really nice eyelight. I’m been experimenting ways of creating it but i just can’t seem to get that perfectly nice round and big dots on the eyes. What are the best ways of creating them in both indoors and outdoors? and which side of the camera should the light be placed?
A friend of mine was explaining that they use a really strong light and diffuse it just above the actors. How far is this true? If you do have any articals on it, please do let me know.
Thanks,
Desh
Comment by Desharado on August 10th, 2007 at 8:23 am
very interesting, but I don’t agree with you
Idetrorce
Comment by Idetrorce on December 15th, 2007 at 9:01 am
Hi Stephanie, great article (which we also covered in class)…
One place I can think of that might have inexpensive fog machines is… yes, Guitar Center- they usually sell those, and are always having “Mass blowout sales”, so that could be one place for a relatively inexpensive fog machine
Comment by Jon Capogrossi on October 2nd, 2008 at 9:20 am
Great suggestion, Jon!
Comment by Christopher Frazier on October 2nd, 2008 at 1:07 pm
Hello there, great article it was very informative.
Just a note for those considering purchasing a Smoke Machine. I have Just 300 dollars on a very good smoke machine. I would just like to say that there are two different types of smoke machines. One is just a regular smoke machine (used in the shot with the rocking chair) and the other is a Fogger or Hazer. This is used more for visible smoke such as steam smoke or Low Lying Fog (Low Lying Fog can be achieved with the use of a Fog Chiller). A Fogger/Hazer generates a more invisible smoke that is much less fractal than what would be achieved using a smoke machine. The smoke emitted from a Fogger/Hazer is much finer and is generally used to make light more visible as seen in all the above images apart from the rocking chair one.
So bottom line is, if your after steam, smoke or low lying fog, buy a smoke machine. If your after rays of light but a fogger/hazer.
Tom
Comment by Tom on November 1st, 2008 at 5:23 am
Thanks for the info, Tom, that’s great advice.
Comment by Stephanie Simpson on November 1st, 2008 at 5:53 pm