How the Size of Your Light Source Affects Portrait Results

Joe McNally brings us a video displaying the effect of a light source’s size. He will test three different soft boxes, two direct and one indirect. Watch as he compares and contrasts the size, in relation to his subject, using large flash. This was shot on beautiful St. Lucia with a local musician, Claudette:

He demonstrates using three soft boxes: first, a 27.5-inch octagonal Elinchrom Rotalux. This is a relatively small source, creating a slightly hard light with quite dramatic shadows. Next, he brings in a 39-inch Rotalux Deep Throat Octabox. The extra depth of the soft box itself scatters the light more smoothly, while the larger size brightens more of the subject’s body and softens the gradient between highlight and shadow.

Finally, the strobe is fitted with a 59-inch Inverse Octa Hybrid soft box. This differs from the previous two in that the strobe head inside the box is reversed, reflecting off the rear of the box rather than straight out the front. This difference creates a greater spreading of the rays, and therefore a more even dispersion of light. This, along with the hugeness of the box itself, casts an extremely gentle light, illuminating Claudette from head to toe.

soft box portrait photography

Through McNally’s samples, we can observe first hand the difference the size and configuration of our light source makes to our photographs, and how we can use this understanding to create the mood and style that we’re looking for.

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