What kind of light modifier should you use? Here's why Umbrellas are great to start with, but lightbanks give you added directionality and control.
Portrait lighting has four major characteristics: color, direction, quantity, and quality. When working with light sources—from speedlights to monolights—the best way to improve the light’s quality is with a modification device such as an umbrella or a lightbank. Each light modifier has its own unique advantages and disadvantages. No matter which one you chose, both devices are governed by the same important rule: The closer that a light source is placed near the subject the softer it is; the further away the light source is, the harder it becomes. So let’s get to the differences between an umbrella and a softbox.
Umbrellas can be downright cheap. A 42-inch Flashpoint White Interior Umbrella costs lest than twelve bucks! They are also easy to use, because if you’ve ever opened a rain umbrella you’re halfway to knowing how to use one. Umbrellas produce a broad and soft source of lighting that could, for the sake of simplicity, be considered to emulate outdoor lighting. When used in the traditional position, umbrellas produce indirect, bounced light that may require more flash output from the light source you’re using. Because umbrellas produce broad lighting, they are easier for beginners to use. You point an umbrella at a subject and bang, you’ve got soft lighting! Use two of them and you’ll think you’re a lighting genius.
Lightbanks, which are often called softboxes, are usually rectangular but can also be octagonal or square. They emulate the soft, directional lighting produced by window light. The key word here is directional. Lightbanks are the light modifiers that many big time photographers use so that’s what many beginning photographers aspire to as well. Because your flash fires directly through a lightbank, it produces direct lighting, even though the lightbank may have a diffusion panel in front of the flash tube to soften the flash. Because you're shooing through rather than relying on reflected light, your flash requires less power output than when using an umbrella to obtain the same lens aperture. Softboxes are available in many sizes, including large ones that, when placed close to a subject, produce very soft, yet directional light. There are lots of accessories available for lightbanks, which as grids or louvers, that make the lighting even across the plane of light.
To show you the visible differences between an umbrella and a softbox, I shot a comparison test using two large light sources. In this corner was a white Flashpoint 16-rib 64-inch parabolic umbrella ($44.95.) In the opposite corner was a 36x48-inch Flashpoint PZ Softbox ($119.95.) As you can see, even an inexpensive lightbank, like the PZ series, isn’t cheap so all that directionality comes with a price. For my test shots I didn’t use any fill light or reflector because I wanted you to see the total effect of the light modifier that was used.
This is the lighting set-up that I used for my test in my 11x15-foot in-home studio. A Flashpoint 620M monolight was placed at camera right, just outside the frame. My first shot was with the 36x48-inch Flashpoint PZ Softbox and then later I used an umbrella the monolight was in the same location. ©2012 Joe Farace
To give me an f/8 aperture and achieve the kind of depth-of-field I like when making a three-quarter length portrait, I set the power on the Flashpoint 620M between one-eight and one-half power using the monolight’s continuously variable output knob. No reflector was used, only the light from the 36x48-inch Flashpoint PZ Softbox and the exposure was 1/125 sec at f/8 and ISO 100. ©2012 Joe Farace
To make sure nothing moved when I switched to an umbrella, I placed gaffer’s tape on the floor to position the Flashpoint 620M now with Flashpoint 16-rib 64-inch parabolic umbrella mounted. Two things happened: One that’s obvious and one that’s not. The obvious thing is that the lighting is much broader, softer with less modeling on the subject’s face and there’s more light spilling onto on background. What is not apparent is that because the light is bounced the quantity is less, so my exposure setting changed to 1/125 sec at f/6.3 and ISO 160.
Unlike umbrellas that are forgiving, lightbanks require some basic knowledge of balancing the main versus fill light (that fill could even be an umbrella or just a reflector) so it won’t produce overly contrasty lighting (unless, of course, that’s what you want.) Softboxes are also slightly more complicated to set up although Flashpoint’s series of PZ Softboxes are the easiest to assemble that I’ve ever used. But choices are what this whole discussion is about. You select the light modifier that matches the kind of portrait you’re trying to make. Sometimes that will require an umbrella, and sometimes it’ll be a lightbank. There is no “one size fits all” solution to lighting. Just as you will select the right lens and ISO for a natural light photograph, when it comes to working with artificial light you need to select the right tool for the job.
Read Part II: What Everybody Ought to Know About The Shape of Soft Boxes for Flash
Joe Farace is the author of the new book “Studio Lighting Anywhere” which is available from Adorama