Octabox (Octagonal Softbox) Sizes and Surface Areas

I wanted to know the surface area of an octabox (octagonal softbox). Typically, octaboxes are sold by their "span," such as 48" or 60". However, the formulas typically available via an internet do not use the span of the octagon. After some digging, here's what I found:

A=0.828(S)(S)    or    A=0.828*(S)^2       where A=Area and S=Span

In other words, enter 0.828 into your calculator, multiply by the span of the octabox (60 for a 60" octabox), and then multiply by the span again (60 for a 60" octabox).

Using this formula, the surface areas of some common octabox sizes are:

79" Octabox = 5168 sq in
70" Octabox = 4057 sq in
60" Octabox = 2981 sq in
48" Octabox = 1908 sq in
36" Octabox = 1073 sq in
24" Octabox = 477 sq in

Keep shooting!

~ Kristoffer Cox