We claim the ornamental design for a spherical lens for a camera, as shown and described.
FIG. 1 is a front view of the spherical lens for a camera in a first position relative to rotation of the spherical lens for a camera about a central axis AA, wherein oblique line shading indicates transparent outer body surfaces, and wherein the back side, left side and right side views of the spherical lens for a camera in this first position relative to the central axis AA are mirror image/symmetrical relative to each other;
FIG. 2 is a front view of the spherical lens for a camera in a second position wherein the spherical lens for a camera is rotated about the central axis AA 45 degrees relative to the first position shown in FIG. 1, wherein the back side, left side and right side views of the spherical lens for a camera in the second position relative to the central axis AA are mirror image/symmetrical relative to each other;
FIG. 3 is a top side view of the spherical lens for a camera;
FIG. 4 is a bottom side view of the spherical lens for a camera; and,
FIG. 5 is a left side perspective view of the spherical lens for a camera.
Any broken line(s) shown are for illustrative purposes only and form no part of the claimed design.