A US patent application made public today hinted that Apple may be toying with the idea of letting picture-loving iPhone users change lenses for the smartphone cameras.

Apple's application for a "back panel for a portable electronic device with different camera lens options" included a diagram reminiscent of an opened iPhone with labelled parts.

The application described a design to let users change lenses that typically are fixed in the backs of smartphones to act as eyes for cameras.

"It would be desirable to provide a structure for a compact device that allows the end user to reconfigure the optical arrangement of the device while retaining the benefits of assembling the device using a pre-assembled digital imaging subsystem," said a copy of the patent application available online.