Lots of great conversations about light are going on in various Facebook groups I participate in. Many of them get into discussing the shapes of modifiers and what diffusion does or doesn't do. Fortunately, I have a wide variety of modifiers available to me, so in some moments of free time last night I decided to test a few of them out. I used a mannequin as my subject for consistency from modifier to modifier and to purposely not be able to see the catchlight that would appear in a real subject's eyes. The big difference between many similar size modifiers of different shapes is in the catchlights. But that is a different discussion. Skin will look very different from the plastic mannequin, however this demonstration is about the shadow edges-- the transition from highlight to diffuse reflection to shadow.
This video clip runs through the following list of modifiers: 36-, 46-, an 60-inch Photek Softlighters, 46-inch Softlighter without its diffuser (10-panel umbrella), 36-inch octabox (with and without the inner diffuser panel), 2x3-foot softbox (with and without its inner diffusion panel and vertical and horizontal), Westcott Apollo Orb (with and without its front diffusion panel), a bare bulb pointing at the subject with no reflector, a 7-inch metal dish reflector, a fresnel lens attachment in two positions (narrow and wide), a snoot, and an optical spotlight.
Here is a series of the still images of most of the modifiers
And here are two slider comparisons of a 46-inch Softlighter with and without its diffusion panel and of a 36-inch octa and a 24x36-inch vertical soft box.
A main point I want to make here is that very often you can use the equipment you already have. We all fall into GAS (Gear Aquisition Syndrome) and/or feel jealous about that wild new modifier the kid down the street just purchased. Yes, as a photographer pixel-peeping at the images we can see subtle differences between the various modifiers. It is up to you to decide if those differences are worth the price tag and storage space considerations. For myself, starting out I would choose a set of Photek Softlighters (at least 46- and 60-inch), an Interfit 2x3 softbox (I really like the quality of the materials, the build, and the price of their boxes + they include grids!), a 1x3 strip box, a 40-inch shoot-through umbrella, and a standard 7-inch metal dish reflector.
Here is a list of the modifiers used in the photos above:
Interfit S1 flash
Photek Softlighters (36- 46- and 60-inch)
Interfit 2x3-foot softbox
Westcott Apollo Orb
Fresnel lens attachment
Paul C. Buff 36-inch Octa (replaced the Balcar mount with a Bowens S-mount speedring)