We love walking through the different neighborhoods - Chinatown, Old Montreal, McGill University, etc. This link might be useful http://www.frommers.com/destinations/montreal/planning-a-trip/neighborhoods-in-brief
Since you are a photographer you might enjoy walking/hiking Mont Royal - there are beautiful views of the city.
If you like bagels you should try the two different brands - Fairmount and St. Viateur. Many people are seriously loyal to one over the other. Each brand has bakeries that simply sell bagels and then there are "cafes" where you can actually sit.
Agree 100% with EB. There is some good food. Cheap: Poutine, must try! More expensive/delish food/friendly ambiance: Bocata on the edge of the old city
Bike ride. And maybe a restaurant with Quebecois wines and local produce. It's been a while but we had a really nice meals at Taverne Gaspar and Chez L'Epicier.
If you are a Napoleon aficionado, the fine arts museum has an interesting collection.
We rented bikes and rode over to La Ronde-the amusement park. We thought it would be closed, as the bike rental guy thought it would be, but it wasn't. This was in September.
Visit St Joseph's Oratory. Stunning. And EAT! Montreal is a fabulous city for restaurants.
Promote your business here - Businesses get highlighted throughout the site and you can add a deal.
--- I got 1 1/2 days in September.