Before I expand on these lighting devices, let me explain that shadow edge is controlled by the size of your light source. Barn doors don’t give you a hard shadow edge because they are barn doors. They do it because they are part of a small light source. The only thing that matters in this regard is the size of the light source from the point of view of the subject so next time you are curious about this, just sit on the posing stool where your subject would be and look at your various light sources. It is their size from this point of view that controls the hardness or softness of of the shadow edge.
Control devices like snoots, barn doors and grids each have a characteristic way of controlling the light exiting a studio flash unit. Photographers getting into the business have a great tendency to be constantly looking at all the new toys available to them that will undoubtedly make their photographs better. This I know because I was once one of them.
First the ever popular and misunderstood snoot. This is in many cases the first lighting gadget that photographers buy once they have their studio strobes. It seems to be designed to assist in the business of lighting the hair. Well, the snoot is not a particularly controllable lighting device and that seats it in the “Of little or no value” section. A snoot is basically a metal tube on a flat piece of metal that mounts to your studio flash unit. The tube is usually only about 3 or so inches across so right off the bat, it is reducing the amount of light coming from your flash unit. The tube is typically 6 to 10 inches long. So what does it do if anything at all? It takes a smaller amount of light (because of the reduced size of the aperture in the metal plate) and lets that light exit the front of the tube. That’s it. It confines the light to a somewhat narrower area than the flash unit by itself but only to a degree so there is little benefit from using it. It does not provide any significant control other than a slight amount of pattern narrowing. After 26 years in the business, I demonstrate how valuable the snoot is to me at my seminars by bringing it out sitting in a clay pot filled with potting soil with a nice ivy plant growing it. I have seen snoots where a small piece of honeycomb material was mounted in the mouth to collimate the light a little. There was an improvement but it still was very poor as a controllable lighting device.
A grid spot attachment is a device that has an inch or so of honeycomb metal mounted into a frame that attaches to the front of your studio flash unit. The purpose for the honeycomb material is to collimate the light into a narrow beam. There are different sizes of honey comb material where the individual holes vary from about an a tenth of an inch up to a quarter of an inch. The narrower the hole the narrower the beam exiting the flash unit. At a distance of 10 feet, a grid with small holes in the honeycomb might project a pattern of light no bigger than 10 inches or so. A grid with larger holes in the honeycomb, will be a bit larger. So what is the benefit of having a grid spot attachment like this? Several.
A grid spot can be used to isolate a subject’s face leaving the rest of their body essentially in shadow. I have used this effect many times over the years in everything from high school senior work to boudoir photography. The light source is a small one with hard shadow edges so care must be used to create a proper lighting pattern such as loop, or Rembrandt. For fashion work, it is easy to create a lighting pattern like Francisco Scavullo did for many years on the cover of Cosmopolitan magazine. The light is fired dead on into the models face at eye level and is then moved just slighting to the side creating a very subtle shadow on one side of the nose. This technique combined with a soft focus filter can be quite striking and is relatively simple to do.
A grid spot can also be useful in highlighting a small area in a photograph without affecting anything else nearby. I have used grid spots countless times in boudoir photography to add a beautiful glow to a woman’s feet in high heels. I have also used grid spots as a bust line augmentation light where the grid is firing from slightly behind the model, over her shoulder gently grazing across the cleavage area creating highlights with shadows thereby enhancing the size of the bust line. I actually had a customer once ask me if I could come to her home and adjust the lights so she looked that big at home. It was pretty funny at the time.
Grid spots are also useful when you wish to add a small splash of color to the background in a very specific place. Simply added a color gel and point the light where you want it. It is important to use a grid that has a flat metal frame around the front so gels can be easily clipped on.
I have used grid spots to fire a long beam of colored light diagonally across a muslin background for specific effect. I have also used them to direct a small amount of light onto a very specific area of an object when doing commercial product photography.
I have found many uses for grids over the years but as with all accessories, they are only as useful as you make them. They won’t do the work themselves.
Lastly, we have the barn doors. These are simple frames that attach to a studio flash unit and have hinged metal doors. Sometimes two doors and sometimes 4 doors. One would ask what the benefits are for one over the other. With a 2 door unit, you can close the doors down to zero opening but the opening will always be a long slit. This is not a bad thing but under certain circumstances it is more convenient to have 4 doors so you can close down in both axis at the same time keeping your light source symmetrical. The bottom line is that if you have a 4 door unit, you also have a 2 door. Just don’t use the other two.
The benefits from using barn doors are not as well known as with other studio toys. Today we have such a huge emphasis on technology doing everything for us that many simple devices like the barn doors are sadly all but forgotten. Barn doors provide control unlike any other device. With nothing more than a quick flip of the hand, you can change the amount of light exiting your flash unit from 100% to 0 % or any increment in-between those extremes. The beauty of this is that the changes made affect both modeling light and strobe tube equally so you can stay in a “what you see is what you get” mode. This is critical for me because I want to know what I have before I press the shutter release button to make an exposure. I do not want to have to look at the back of my camera to see how my lighting is. I watch photographers everywhere spending more time looking at the back of their digital cameras than looking through it at the subject. I want to know that what I see is what I will get and the only way to know is to have a balanced set of lights and to use methods of controlling their output so any changes made are equal for both modeling bulb and strobe tube.
Someone will say, just turn down the output of the flash unit while it is in the tracking mode. Sadly, many, many flash units are not linear with the amount of change provided in their controls. This means that reducing the amount of strobe output, reduces the amount of modeling bulb output by a disproportionate and usually lesser quantity. For many flash units, the tracking feature is only a rough approximation. I recently tested the just released Novatron M600 mono light and plotted a graph of it’s strobe output as compared to its modeling bulb output and was pleasantly startled at it’s nearly ruler flat tracking over a 5 stop range. It’s the first I have encounter that was this accurate.
Ok, back to the barn doors. When I am adding a bit of accent light to a portrait subject’s hair, I have to have control over the smallest changes in light output. For this reason, I use a set of barn doors on my hair light. So frequently, hair light is overdone and blown away. I teach my students to begin small and gently build up the hair light until it’s just enough to provide a beautiful separation and still show detail in every hair. This kind of precision is easy with barn doors because of the control you have. I open my barn doors on my hair light just a crack. Perhaps a half inch or so depending on hair color while my flash unit is pointing behind and away from the subject. Then I gently rotate the flash unit toward the subject until just a kiss of light is gently touching the side of the subject’s head providing me with perfect hair light. This works perfectly for one or two people as I can train my hair light to reach both people and give one more light than the other if need be due to differences in hair color. For larger groups, it’s no more difficult than turning the flash unit upward and firing it toward the ceiling where a large reflective panel is mounted above the shooting area. I can now provide a beautiful kiss of hair light on a family of 8 or 10 and control the amount of hair light precisely by simply opening or closing the barn doors. Simple.
Like the grid spot, one can also use barn doors to fire light into small areas of a photograph for various effects. Lighting a model’s shoes or the calves of her legs or adding a deep blue accent light to the edge of her black leather jacket are all easily done using barn doors combined with color gels.
Barn doors are excellent when you wish to fire a bit of light onto a specific area of your background as you can easily control how large the area is and how much light reaches that area by opening or closing the doors.
For me the most significant thing that barn doors allow me to do is to control the amount of main light that I am using. Most of the time, my main light is a simple 7 foot tall diffusion panel. I use this because it provides control like no other lighting device. I get to decide what size of light I am using and can change from huge to extremely small in a matter of 2 seconds by doing nothing more than changing the distance of the flash unit to the panel thereby making the lit area on the panel larger or smaller. Combine this with the use of a set of barn doors and you have unlimited control over both size and quantity of light. By adjusting the size of the barn door opening and the distance to the panel, I have total control over the size of the light and the quantity of the light. I can close the doors way down to only a 4 inch square and move them very close to the panel for a very hard edge defined quality of light. I can also move my flash unit back and enlarge the area on the panel being lit providing a softer quality of light. I can also open the doors up all the way and move the flash unit in close and create a small light source at a higher brightness level. The control possibilities are huge and the best part of this is that since the changes in light output are mechanical because of the barn doors, I will always get what I see.
Barn doors are my favorite tool in the camera room as well as on location. They provide incredible control while giving me precisely what I see. That’s a pretty big advantage when there is a lot of money riding on getting it right the first time.
I hope this has been helpful.