What Professional camara to buy?

Should I Buy the nikon L120 or the D3100

I want the D3100 but My father wants the cheapest One which is the other one… Also for the L120 do you change the lens?

1) the L120 is a bridge camera (you can't change lenses)
2) the D3100 is an entry level DSLR

neither are PROFESSIONAL cameras… They are just somewhere to start…

look at the Fuji HS20 for something with a LARGER lens option…

Neither of these is a professional grade camera. The L120 is a bridge camera, which is basically a point and shoot camera with a bit more zoom and a few manual controls.No, it can't exchange lenses, unlike the D3100.

The D3100 is a proper DSLR, albeit a lower entry level one. It achieves the same image quality as real professional DSLRs, such as the $1500 D300s, it just lacks some of the advanced features that amateurs likely won't ever need anyway. It still depends a lot on being in skilled hands though, don't expect it to produce pro quality shots just at the press of a button. A DSLR merely enables a pro to bring his skill to bear, just like a good racing car enables a pro driver to win races - but just like you can't expect a newbie to win races just by putting him into the right car, don't expect to get pro quality shots by using a DSLR.

Nikon d3100 is the best buy