Many times I'll want to brighten up a bird in the shadows or to take images on cloudy/overcast days or even rainy days. One way to make the subject pop is to add light. This can be done with simply using a flash unit, but the light disperses widely and might not project far enough to reach the bird or subject. Below is a flash unit attached directly to the camera just for demonstration purposes. (I only shoot with the flash directly on the camera when, for some reason, I can't get the flash off-camera.)
To extend the distance the light from the flash travels and to concentrate the light on the bird or subject, I use a Fresnel flash unit. There's one pictured below, a Better Beamer Flash Extender setup from Visual Echos. I've only used this brand, simply because it works and it's reliable. The plastic side pieces vary for different flash units. The strap and the Fresnel lens is pretty much the same in each kit. (I get mine from B & H Photo.)
Here's what the Better Beamer Flash Extender from Visual Echos looks like on the flash unit. This will concentrate the light onto the bird or subject and add one or two stops of light. Sine this also makes the flash more powerful, be prepared to dial in -1 or -2 on the flash exposure compensation dial.
The flash unit puts out daylight temperature light. On a cloudy or rainy day or in the shadows this can look fake and contrasty. So I borrowed a technique from studio and fashion photographers and started using gels on the flash unit. After some experimentation, I settle on these three products, buying each part separately. The Honl Photo Speed Strap, the Honl Photo Professional Color Effect Gel Filter Kit (CTO warming) gels in various powers and the Honl Photo Rollup Filter Case. I cut down the width of the CTO gel, so it fits inside the Better Beamer Flash Extender and is just wide enough to cover the flash units lens. (See below.)
Here's the CTO gel inside the Better Beamer Flash Extender, all held to the flash unit with the Honl Speed Strap. To do this, you have to use the Honl Speed Strap in place of the Better Beamer strap. The CTO gel has velcro strips on it and won't stick to the Better Beamer straps.
The first image of the Peregrine Falcon is without any flash and looks dark and rather bland. The second image is with a flash unit dialed down -2 stops and using a 1/2 CTO Gel, the image looks brighter and warmer. I use the 1/2 CTO gels the most. If you like warmer or cooler images, you can move up to 3/4 CTO or 1/4 CTO strengths.
This Peregrine Falcon was photographed on the Eagles & Peregrines of the Outer Coast Photography Workshop I lead each February and March. More information about these workshops can be found here.
I just did an internet search and the Better Beamer is available at B & H Photo (order the right size for your flash unit), and the three Honl items are available at Amazon. I'm not an associate or affiliate at either place and only post equipment items that I use.
Enjoy! Thanks Tim