I have done my own experiments using previous information and with the discovery of a very inexpensive material for the backdrop that doesn't require sourcing it from China. I used an old camera for these images so they aren't the greatest quality.
----- Light rings and accessories ---------
Purchased from SuperBrightLeds.com.
In addition to a green and blue ring, I also needed a power supply, dimmer and adapters. If you use the following invoice as a guide, note that it would be best to get two adapters so that you can permanently hook up the green and blue ring each to an adapter eliminating the need to undo the wires. I thought they would plug in to the light ring but the wires are just exposed.
I have only used the green light ring. I measured the diameter of my camcorder's lens then cut a circle in the center of an old plastic yogurt lid. I attached the led ring to the plastic lid and it sits
securely on the front of the lens creating even spacing of the lights.
----- Retro-reflective material -------
An earlier post of mine in this thread noted that there have been two previous attempts at a DIY system documented elsewhere. The frustrating part is that most are unwilling to disclose where they got their material. When they do it's too expensive (3M) or complicated (China). Some have speculated on the use of paint or a projection screen.
A search on Ebay yielded a retro-reflective tape that is ironed on to a fabric. This was convenient because the seller is in Canada (my home country) and offered a full money back guarantee if unsatisfied.
This helped me to take a risk on it and I am very glad I did.
After placing my order, I did a test then created a 5ft X 4.5 ft backdrop. The cost was $50. Add that to the light ring setup and my total cost was about $100. However, I would want to create a larger backdrop so that cost would increase. But it's still a lot less expensive than even the cheapest alternative I have seen.
The retro-reflective tape is available in several different sizes, I chose the 6" width because it would mean less ironing onto the fabric. I had hoped to just tape it on the wall but it is necessary to iron it onto something to successfully pull off the plastic film over the top. Here is the link to the seller's Ebay page, but check my later post below for new information about a less expensive 39" size.
This is what it looks like.
------ Video results ------
This is a test video I did today. I just grabbed an image for the keyed backdrop which isn't high resolution.
This certainly isn't broadcast quality but is great for my purposes because it's dirt cheap and very easy. As has previously been posted, you just hang the fabric and turn on the light. I originally had the dimmer too low and had to increase the brightness to get an even green color.
I imported the footage into After Effects CS4 and used KeyLight (1.2) to remove the green. The moment the color was selected the program did a great job eliminating the background with only some minor
changes to the other settings.
I was unable to get the embedded video to work so here's the link: http://www.vimeo.com/17036277
----- I hope this helps. Let me know if you have any questions. -----