Basic Concepts of Light Shaping Tools
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My Broncolor Para 177 - the most beautiful light shaping tool that I have found, but a bear to setup and transport
Hey folks
If you like flash, and I know that some folks don’t - I feel bad for them, you also like light shaping tools, or would if the myriad options made sense to you. Certainly some of the marketing can be confusing and in some cases, misleading, so let’s clear things up today.
Size Matters
Most of the time when we talk about light shaping tools, we are talking about making light that has what we call softness. This is occasionally called “wrap” which is invalid from a physics perspective but easy to understand artistically.
At the easiest to understand level, at a given distance, the larger the surface area of the source, the “softer” the light. Light is both a particle and a wave, and moves in straight lines, unless under the influence of a massive gravity well. So unless you have a portable and controllable black hole, light goes straight. It does not bend, it does not curve and it does not go around corners. When we understand this the value proposition of a larger source makes simple sense. With a larger surface area the light can come from more directions, giving the perception of wrap, and it is this look that we call “soft”.
Want softer light, bigger source. It really is that simple.
This confuses folks because they have been led to believe that diffusers make for softer light. They don’t. Let me say it again. Diffusers do not make softer light. What they do is make the source more even in luminosity across the area of the source.
This means that those little plastic dome diffusers do not soften light. What they do is even out the light across their surface area. This consumes power of course because the diffuser is in the path of the light, but it can help depending on the size of the diffuser and how close it is to the subject and how large it is relative to the subject. A dome diffuser makes no difference on a speed light that is 6 feet away from a person other than chewing up power. However, that same dome diffuser can be effective if you are doing macro shots of very small things, things with a much smaller surface area than that of the dome diffuser.
Which as you have figured out is really about how large and close the source is relative to the subject.
Light Shaper Shapes
So why all the different shapes in light shapers? The fundamental design reason is managing spread of light with a secondary consideration of what the reflection of the source looks like.
Octas, paras, and such exist not solely because of spread, but because the shape is more pleasing to some in their reflections, such as in the eye of a portrait subject. A para with the same surface area as a regular soft box is not softer at the same distance, it simply produces a different image when reflected. Hence we have both. The light is not different, the perception of the validity of the reflection is what matters.
A strip box is taller than it is wide by some ratio from 2:1 to perhaps 6:1. The shape helps the creative manage spread or spill. Very convenient when the subject that you are lighting has similar proportions AND that you want to shape your light to emphasize those proportions and not send light anywhere else. Very handy for fashion, because you want to create areas of light and shadow. Very often used in automotive photography to call out a designer’s line or curve in a body panel. Strips are also used as delimiters from the rear to create separation limning between a subject and a background.
Big rectangular light shapers are good for furniture and room sets, because they have such a large surface area and when placed properly can look like sunlight coming through a non-existent window. The shape echoes the subject. They also do a great job of creating the look of a heavily overcast day if they are much larger than the subject relative to the shaper / subject distance.
Are paras better than octas? That’s up to you. Both have a similar reflective shape, but paras have more arms than octas and so the reflection looks rounder. In either case, you can find either that support front firing lights or rear firing lights. A rear firing light uses more power because it adds one more level of diffusion inside the unit. Whether that makes a difference will be unique for each shooting situation.
Diffusion Panels in Softboxes or on Umbrella faces
Now that you know that diffusion panels do not soften light, only spread it within the container, you understand that their contribution is all about evening out the luminosity across the surface area of the front of the light shaper. They do nothing to control spread or spill. Do they make a difference? It depends. Try your shaper with and without the internal diffusion panel at the same light to subject distance and with the same subject and find out if you see a difference and if you do, which one you like better. Remember that as light source to subject distance increases, the impact of that internal diffusion panel is going to be felt a lot less. That’s basically physics, marketing hooha does not change reality.
Umbrellas vs Softboxes
Why choose one over the other? Fair question. Umbrellas are the easiest light shaper to use effectively because they simply make a larger surface area and are quite forgiving because they offer minimal control of spill or spread. What’s the difference between a shallow and a deep umbrella? The only difference is the spill pattern. The deeper the umbrella the less spread you get. Some makers market parabolic umbrellas where all the light rays from the source are alleged to emerge completely parallel to each other. In practical usage this is exaggerated but you do get a sharper falloff because of spill containment. Choose according to YOUR needs not the marketing.
A soft box is different from an umbrella in terms of power efficiency. If you take an umbrella of diameter 40” and compare it to a round soft box with a diameter of 40” with the same depth and the source of light in the same shape as the umbrella, and leave the front diffusion panel off, you will be very hard pressed to see a difference in the light. If the shape of the shapers is identical, they work the same way.
Most soft boxes are much deeper than an equivalent sized umbrella and so the emerging light is more focused with a more obvious fall off. When you add that front diffusion panel to the soft box you also even out the luminosity across the surface area. However if you have a diffusion panel that goes on the face of your umbrella, you are accomplishing the same thing.
Umbrellas in general are less expensive, easier to set up and tear down, and perhaps take up less space in transport. Used well, umbrellas produce very lovely light albeit with more spill and less directional control, but if those things are not important in your use cases, umbrellas may be your thing.
Beauty Dishes
These light shapers have their own life in fiction. A beauty dish is a simple dish, with a reflector suspended in front to the light source to force all the light rays back into the dish. The dish bowl and reflector are in the better units shallow parabolas to influence the exiting light rays to be be mostly parallel for real spill control and enhanced contrast. Designed for use in a specific orientation the directionality enhances bone structure, hence the naming when used well. One could accomplish the same thing with rear firing parabolic soft box or umbrella.
Grids , Snoots and Scrims
Grids are simply a tool to control spill and direction. The tighter the grid, the more directional the light is and the less spill there is. A snoot cuts spread dramatically to produce a more spotlight look. Add a grid and you have a very focused light, with use as a hair light a popular outcome.
Scrims are just another way of saying diffusion panel. No softening is added unless the scrim enlarges the effective surface area of the source. We find scrims for beauty dishes very commonly and all they do is even out the luminosity across the surface area. In a well designed beauty dish, my favourites being the Canadian designed MOLA Softlights, the addition of a scrim makes no practical difference.
I’m not speaking of gels here because they are not light shaping tools, they impact the colour of light so I am not forgetting them, merely ignoring them in this article.
Conclusions
Light shaping tools are wonderful options and ways to change the outcome of your creative efforts. Unlike ambient light which is mostly uncontrollable, shapers put you in charge of the light. Which shaper you use is entirely up to you based on attaining your creative vision. What works for someone else, may or may not work for you. Brand may or may not matter to you depending on your willingness to invest and how hard you will work your tools. Try anything but remember that no light shaper changes the laws of physics, no matter what marketing or the Internet says. Hopefully you find this article of use.
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I'm Ross Chevalier, thanks for reading, watching and listening and until next time, peace.
