Meat Packing district (west of 8th ave around 14th st.) is great for photos. During the week, the financial district is interesting, especially around 9am and 5pm (as people come and leave work). Wall St is cool, as is Stone St (small section is pedestrian only). Williamsburg can be interesting especially for B&W, but don't bother on Saturdays as no one will be out (it is a Hasidic neighborhood). Walk across the Manhattan Bridge from Manhattan and back over the Brooklyn Bridge. This way you get the best views of the Brooklyn Bridge, a short walk through DUMBO in Brooklyn and then you get to experience the majestic Brooklyn Bridge on your way back.
In Vancouver, I suggest, if you have the time, to head over to Vancouver Island for a few days. Tofino is glorious. Botanic Beach in Port Renfrew (90 minutes west of Victoria) is really amazing. Make sure you time it around low tide. The beach is covered with dozens (hundreds?) of tide pools carved out of the limestone. These are filled with sea anemone, urchins and other wonderful marine organisms.
Enjoy your trip.