First, thank you lodtrack and Dave_x10_L for your replies.
1) I varied the distance between the camera and receiver from 2 feet to 25 feet and observed no change in image quality. The radio-frequency (rf) link worked remarkably well for one of the 4 frequencies available. The other 3 frequencies suffered disturbances from other sources - presumably cordless phones or wireless routers in the area. The rf link appears to be pretty solid and quite adequate for the Xcam2 camera.
2) The resolution I measured is that of the CMOS sensor plus lens (which I did carefully adjust to get the best focus) and represents the best it can do at any distance. I suspect the CMOS chip itself has a resolution of approximately 128x100. There's a modest additional loss of resolution due to the molded plastic lens and analog rf-link. See illustration of effective resolution at
http://www.flickr.com/photos/ghbrand13/5547494888/ 3) Clearly the closer the camera to the object of interest the better. After I uploaded my previous message I moved the camera to a bit less than 5 feet from the bird feeder and of course was able to see the birds more clearly since they occupied a much larger fraction of the image than when I had the camera 20 feet away. I would guess Dave_x10_L you had your camera much closer to the hummingbirds than the 20 feet at which I originally did my evaluation. Bottom line - for an inexpensive camera like this, to use it for an application like birding it must be very close to the subject.
4) I'm glad to hear that the X10 cameras really are weather-proof. I'd like to mount my Xcam2 right in front of the bird feeder but have been reluctant to do so for fear that rain and sunlight would destroy it unless I put some sort of transparent covering like a dome over it. Of course I wouldn't expect it to hold up to the midwest tennisball sized hail that did $20,000 damage to my home in 2001...
5) I'm curious to know how well the pan-and-tilt mechanism holds up to rain, humidity and morning dew. Has anyone tried this?
6) I also got the phone call from X10. While I suspect the call is in part motivated by possibly getting a customer to do a last minute upgrade to new merchandise (which I didn't), I also think it's prudent to make sure the customer really does understand that they're buying "refurbished" stock. While "refurbished" stock sometimes means new overstock, the items I bought appeared to be returned items that had been repackaged in labeled plastic bags. The items showed no sign of significant use - no scatches, dirt, etc. and I have no doubt they work as well as new. I do wonder if they have a large stock of returned items because buyers are disappointed by the low resolution.
7) Conclusion: I only paid $69 for the whole thing and by positioning the camera close enough to the bird feeder it'll accomplish most of what I want it to do. I'd really like to have high resolution with remote optical zoom but I'm not willing to shell out $600+. I got what I paid for and that's OK. Still, I wish X10 would provide at least minimal technical specs like effective resolution.
