Photography a bridge w/lights (nightime)

[Andy]

I was wondering if anyone could tell me what F-stop to use when shooting a bridge w/lights on it at night. Everytime I try, the bridge lights turn out fuzzy (not crisp). I am using a Nikon N90s w/35 - 70 Nikor on a sturdy Bogen tripod. Any tips would be appreciated.

[Richard Knight]

I doubt that the fuzziness you describe has anything to do with your aperture setting unless you are losing DOF. Are certain lights crisp along a plane parallel to your camera body and others soft? If so then you may need to stop down or adjust your hyperfocal distance. I would suspect that the problems are more atmospherically related (fog or haze) as you are photographing around water with the ambient temperature changing faster than the water temperature. Try shooting just before sunrise (in the summer) or just after sunset (in the winter) as the air temp may be closer to the water temp at this time. Also try to pick a day that has low humidity (not always practical in the summer in the south). Another problem you may be having is if the bridge is a suspension structure (they are designed to move). If this is the case, you may have to wait until traffic dies down(which will also help to cut down on emmision related haze) or shoot just after sunset when there is a faint glow in the sky to add light to the scene and allow a shorter shutter speed. If possible try to combine as many of these factors as you can. It's hard to tell without more info on conditions and exposure specifics.