Any of the cameras you mentioned will fill your needs.
I have not seen any reports about noise levels for the Panasonic FZ7. But the previous FZ5 camera had more noise that the other cameras you listed.
All of these cameras have the necessary manual controls that will let you expand your knowledge of photography.
Are expensive cameras "worth it"?
If you are interested in photography...yes.
If you want to take photos and not worry about a lot of buttons and such.....no.
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I am looking for a 10x optical zoom mainly to be able to take outfield pictures - big braves fan. I thought I had it narrowed down but now, sony 's dsh h2 and h5, canon's s3 is and Panasonic has thrown the fz7 in the mix. I am a newbie but I would like to find a camera i can grow into. there seems to be such a range of costs and are the more expensive ones really worth it? The other thing I get concerned about is the cameras the have high noise levels. Please help!

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