"Camera man" and "smilin man" are the names the narrator gives the two strange men trespassing on the Cains' property in Toni Cade Bambara's short story "Blues Ain't No Mockin Bird."
As the story unfolds, the narrator is playing outside her Granny's house on a winter's day, soon before Christmas. She is playing on the tire swing with her third cousin Cathy, and their twin next-door neighbors, Tyrone and Terry. While the narrator is waiting for her turn on the swing, Granny comes out to the porch and orders the narrator to "tell that man we ain't a bunch of trees." It's then that the narrator and the rest of the children notice a man with a camera walking through the meadow, heading towards the Cains' house. Camera man approaches Granny, explains his desires to film her house, and compliments her possessions, directing the camera around the yard to take in "the pecan barrels, the sled, me and Cathy, the flowers, the printed stones along the driveway, the trees, the twins, the toolshed." When Granny gives camera man a hard time, a second man approaches, who the narrator calls smilin man.
The narrator calls him smilin man because he is "smilin up a storm" as he explains they are filming for the county for the sake of the food stamp campaign. He continues to smile as he notices Granny's vegetable garden and asserts that, if other people in Granny's social class grew their own vegetables, "there'd be no need" for food stamps.
In short, camera man and smilin man are there to film Granny's state of poverty and how she handles it in order to convince the county not to spend money on food stamps. They are there to make a mockery of Granny's poverty and the poverty in her social class.