ok, so i took the camera out last night and had a play around.
ISO 100, f8, 30 seconds
ISO 100, f4, 10 seconds
ISO 800, f4, 5 seconds
ISO 1600, f4, 5 seconds
ISO 200, f4, 30 seconds
ISO 400, f4, 30 seconds
ISO 100, f8, 86 seconds!!!!!!!
ISO 100, f5, 39 seconds
so while f8 might be good in the city under a bridge that is really well lit, unless i plan on using 2 to 3 minute exposures, using a lower apeture works better.
also i told the missus about how you said people on the forums said that f8 was the sweet spot for shooting at night, and said that every lense has an 'ideal' apeture setting that isn't always the lowest or highest setting the lense can do, and she said that just because it is the 'sweet spot' as you say, doesn't mean that it will take the best picture at that setting in every situation. and she also made a comment about the fact that you were told that on a forum, and then proceeded to make a rather amusing comparison to how just because everyone on this forum says that if you wind a stock r33 turbo up to 15psi you won't make any more power, that this is actually the case.
*waits for some idiot (who has never tried it, and doesn't know anyone who has tried it and is just going off the info given by 100 other people who have also never tried it) to say that a stock r33 turbo won't make any more power at 15psi than it will at 12psi to prove her point.
LOL