Never had that problem with the S5. Not a big filter fan but the tube that attached to the camera body and surrounded the zoom, in conjunction with the lens, made a nice protective barrier. Of course, that made the camera less "pocketable". But for the SX50 that tube would have to be almost as big as a tennis can. :shock:
Well, looks like a spoke too soon. Apparently there no longer is a tube adapter available for the SX30- SX50 cameras as the end of the telephoto is threaded to accept filters and the tele or wide angle lens. Sorry about that. Short thread about this on DPReview:
http://forums.dpreview.com/forums/thread/3117569
I still have and use this camera's grandfather, the S5 IS, withe 12x zoom. It takes very good shots but is very pale in comparison to your S50. The best purchase I ever made was the Canon (or aftermarket) lens adapter. Even if you don't purchase the telephoto lens (which works very well,btw, no light loss, but with your zoom you would need a tripod) when you attach a 58mm filter you have great protection for the lens glass and the zoom mechanism. Water, salt and especially sand can result in a jammed camera and expensive repairs.
Check out Wasabi batteries and read the reviews on Amazon.
Knopless is right. You need to pay attention to the buyer's and seller's ratings on ebay. I use it but feel more comfortable on Amazon. Good customer service.