I have a bright LED shop light that I’d like to use for photography at home. I’m making a soft box, and the light is 33 inches x 3”. I feel as though my light box won’t be big enough to be worth the effort; the surface area of the white fabric would be 36” x 12”. Can you shed light on this? Am I correct?

If your LED shop light measures 33" x 3", creating a soft box with a surface area of 36" x 12" may not give you the softness you're aiming for, as the fabric area is only slightly larger than the light itself. Ideally, a softbox works best when the light source is significantly smaller than the diffusion surface, allowing light to spread more evenly, creating softer shadows. Expanding the diffusion area to 36" x 24" or larger would enhance the effect, providing softer, more even lighting.

I was going to build two soft boxes at my dimensions since I have two of those lights. What if I built one larger box and used the two stacked LEDs?

Using a single larger softbox with the two stacked LED lights is a great idea for achieving softer, more diffuse lighting. By stacking the lights within a larger diffusion box, you create a broader light source, reducing harsh shadows and providing more even illumination. Spacing the lights slightly apart within the softbox will further help light spread uniformly across the diffusion surface.

I have two pieces of wood: 3/4” x 4” x 8’ cedar boards.

With two cedar boards measuring 3/4" x 4" x 8', you have a total of 16 feet (or 192 inches) of wood. An ideal size for a larger softbox would be around 36" x 24". For this setup, you’d need two 36" pieces for the long sides and two 24" pieces for the short sides, totaling 10 feet, leaving you with 6 feet of wood for additional support.

Could I use more of the six feet for a bigger, more effective box?

Definitely. You could go up to a 40" x 30" box, using 11 feet 8 inches, leaving you with around 4 feet of wood. This setup would give you a broad diffusion surface for softer lighting, making it versatile for various photography needs.

Ok, what about even bigger?

To maximize wood usage, a 48" x 36" box would use nearly all 14 feet, providing a very soft, large light source. This size offers exceptional soft lighting, suitable for larger photography setups, though it may be a bit unwieldy.

Subjectively, what’s most ideal in my situation?

For your setup, a 40" x 30" softbox would likely be ideal. It provides excellent soft lighting, is manageable in size, and effectively diffuses light from your stacked LEDs for versatile photography without being cumbersome.

Let’s go with 40” x 30”. Specs as markdown table, please.

Here’s a markdown table for the 40" x 30" softbox:

            | Component            | Quantity | Dimensions | Description                                      |
            |----------------------|----------|------------|--------------------------------------------------|
            | Long Side Frame      | 2        | 40" x 4"  | Cedar board for long sides                        |
            | Short Side Frame     | 2        | 30" x 4"  | Cedar board for short sides                       |
            | Diffusion Surface    | 1        | 40" x 30" | White fabric                                     |
            | LED Lights           | 2        | 33" x 3"  | Positioned stacked within the softbox            |