Prime lens for D3s?

Hi all,

I just received my D3s last night, and I tried my 50 1.4G on it - but I don't know if I like it - it was so slow to focus, that I almost decided to sell the lens. It just kept hunting without locking for 5-10 seconds, at which point I would just give up. Is there no af focus assist light on D3s?

My main question though is - would any other prime Nikon lens focus faster in low light conditions? I got this camera for night time street shooting - no flash would be used. And I don't feel confident in my 50 1.4G after yesterday's trials..or is there some ngiht time focusing option on D3s that I haven't found yet?

I appreciate any responses and tips on using D3s at night with poor street lighting and with a prime lens!

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Panasonic FZ50, Panasonic FZ7, Nikon D700, Sony R1, Nikon D3s, some lenses.
http://www.vnkphoto.com