为摄影师摆姿势的舞者（窗前的舞者）

Degas painted this around 1875, when photography was still young and a dancer might spend an afternoon holding a pose for a camera the way she once held it for a painter. The ballerina stands on a bare studio floor in front of a tall mirror, checking her own line, and beyond a big window lie the snow-covered rooftops of Paris. The photographer himself is almost absent. Degas records his presence with a single thin leg of the tripod at the edge of the room. It is one of his behind-the-scenes moments, the effort before the show rather than the show itself. And the daylight pouring through that window is not only mood, since a photographer of the 1870s still needed strong natural light to make the exposure work at all.