I have a Sony a200 and have been using a Sigma 70 - 300 that I previously used with my Minolta Maxxum 5. I am somewhere between beginner and advanced and have a small budget. This lens was repaired 3 years ago for a bad focus(?) ring. It just started making a nasty, almost a grinding noise when the camera is turned on or off. I am looking at replacing this lens and would like to stay under $275 . Any opinions on where to shop? Stay away from? Tamron? Sony? Sigma? Kinda under the gun here...Kids High school events started last weekend. Thanks for any and all comments. Need more info? Just ask, please.