>>2683377As I guessed, you're overexposing it. You could pull f/2.8 1/60 with Superia 400 and get a much better result. Be more confident with 1600, you can expose at 1/250 to 1/500 at full aperture for Japanese streets and not break a sweat. The best thing about it is allowing for using teles in street work at night. If you have a fast nifty-fifty, you can do the same with ISO 400 or 800 and get a cleaner result.
Here's f/2.8 at 1/125 or 1/250, don't remember which, Superia Premium 400.