Sigma 20mm f1.8

Hi experts

I need fast lens and now I have chance to buy the 20 mm sigma lens for my D200 8" Aquatica house.

Is she to narrow or not to wide to be used in green and sometimes murky waters. I know i should buy the 15 mm Sigma but I already have 10.5 Nikon.

What do you think. The f1.8 is interresting but i also read reviews about how horrible she is at big f

Any comments would be appreciated

Kvedja

Gisli A.

web.mac.com/gassa

Brandon Cole uses the lens and he is pretty demanding. He did have to test out and return 3 of them before he got one he really liked.

Regards,

James Wiseman