So, this is a long exposure taken at daytime correct? Heavy ND and something like f18?
Exif says 1 second at f/11. Assuming this is near San Fran (looks like the Marin coastline), the 5:30 p.m. time is pretty close to sundown.
Also, without exif you could still surmise a shorter exposure time because the sea would be flattened out otherwise.
heron88 explained it for the most part, but the time in the EXIF is wrong. I forgot to change the time on my camera, so it was off by nine hours when I took that shot...oops! (Thanks for mentioning it; I've just fixed it in the camera!) It's actually a morning scene, not long after sunrise.
To answer your question, Schtumple, I got the longer exposure by using a CPL and a graduated ND (over the sky). As heron88 pointed out, it was shot at a time of day when the light was quite low to begin with, so I didn't need any really dark ND filter to get to a 1-second exposure.
Oh, also, it's not north of SF but south of it, in Pacific Grove. That's Asilomar State Beach.
Arigato! Interesting. The first thing I did was try it out in B&W. I kind of liked it that way. The thing I don't like about the shot is it looks distorted. I have to go back and redo it. I can't seem to get the perspective right.
The perspective doesn't bother me at all. The distortion of the reflection helps to make the actual architecture look 'correct' by comparison, at least it does to my eye. But if you do go back, I hope you'll share the resulting shots here as well!