I'm going to put the RDS back on the Panny FZ50 see if I can find some cooperative flying birds and evaluate how it focuses and has done better for me for BIFs. So far with what I've tried with the SX30 has produced very little positive results.
If you are a bit handy with tools you can try RDS with very little expense. Walmart sells a couple models of cheap plastic sights for BB and pellet rifles and they work GREAT. The mount is the most important part. The best mount would hold the sight rock solid and in the exact same alignment every time it's inserted and tightened in the hot shoe. My first mount was home made from parts I got from a old 35mm collapsible fan reflector flashbulb attachment and a dovetail grooved .22 rifle, A Ruger 10/22, scope adapter rail. It let me put the RDS on the hot show but it was prone to getting knocked out of sight-in alignment with just a small bump. For a long reach telephoto with a small center spot for autofocusing the lens the alignment of the red dot to that center point is very important.
One of the techniques if it can be called that for using the RDS is to pre-focus on something you estimate to be the same distance as your target bird. I haven't had much luck getting the SX30 to focus on flying birds within the desired range for a quality photo. Now, I'm anticipating the flight of the target and pointing the camera at something it can quickly focus on that's at the same distance as the target bird. Once focus is set with a halfway shutter press I go back to panning with the bird and let loose a continuous burst until it's out of range.
There's branch close to my seed feeder that's free of obstruction, but the dang camera can't seem to focus on it. So by a little trial & error test shooting I found a nearby leaf that's the same distance and is a good focus target. So now I put the dot on it and half press then wait for a bird to land on the limb. Actually I don't put the dot on it but a little above it to compensate for parallax error because I sighted-in on a long distance target. For close shots you've got to learn to compensate.
Anyway, is there anything else you'd like to know? I'm running out of babble right now.
Mark
I found these pics of my first RDS & mount
http://img87.imageshack.us/img87/913/rdsscopeoncamerans3.jpg
Here's a simulated view
http://img87.imageshack.us/img87/7100/rdsandviewfindercomposivl5.jpg
Where the shoe part came from
http://img261.imageshack.us/img261/2697/oldflashvv6.jpg
From my first evening with RDS
http://img452.imageshack.us/img452/4750/rdstconcompositelq3.jpgold