DIY Central: DIY Flash Extender

DIY Flash extender

I recently bought a used Canon EF 400mm 5.6 lens and a Canon 430EX flash. My goal for the lens was to use if for bird photography, and to ultimately use the flash as a fill flash. I had seen photos and commentary for products like the Better Beamer, which "extend" the distance that can be illuminated by a flash. They cost about $40 or so, and of course are more difficult to find in Canada. So I decided to build my own.

Materials

Fresnel lens: $1.49 (Zellers)

Corrugated cardboard (Coroplast): $4.99 (Home Depot)

Velcro: $1.00 (dollar store)

Scissors, X-acto knife, Sharpie

Methods

1. First, I needed to determine the focal length of my fresnel lens. This is the distance that the lens will project a sharp image of a distant object on a flat surface. I used a desk lamp mounted about 6 feet above the ground and was able to create a nice image of the lamp bulb on my floor when I held the fresnel lens about 7" - 8" above the ground.

This is the distance the I will mount the fresnel lens from the front of my flash.

2. Next, I cut the measured and cut the coroplast like so...

Note the velcro on the inside of the surface that mates with the flash, and the outer tips which will mate with the fresnel lens.

3. Then I mounted the whole contraption to the flash...

4. Testing and aiming:

I used a wide angle lens and a wall to ensure the lens was centered on the central focus point on my canon 10d. Note that in the following two photos I was focussed on the center of the 4 posted on the far wall.

Too high.