I have now had an adequate amount of time to use the new Harbor Digital Flash Extender and it really works extremely well and is very easy to install. I have the Better Beamer flash Extender and used it quite a lot for adding fill flash but it was not all that easy to install on my 580 Flash unit. The new Harbor design slips on and off and is also easy to aim. I have use it extensively over the last month and it really does work extremely well and adds a nice soft light, not harsh at all. I do plan on testing it at the various zoom angles to see what pattern of light it provides to see what may be more useful depending on how far away the bird is. I have not removed the inner flash lens as other people have done simply because I have not needed to. This may extend the range even more which would be useful to capture flight images as well as larger birds. I use a Canon 500mm IS f4.0 lens with a Canon Mark IV body that covers most of the ranges I usually photograph birds in. All thing...