The ornamental design for a camera, as shown and described.
FIG. 1 is a top right front perspective view of a camera showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines in the drawings are shown to illustrate the portions of a camera in which the design is embodied and form no part of the claimed design.