Patent ID: 7636521

Claim:
A camera system comprising a lens unit and a camera body to which said lens unit is detachably attached via a mount, said lens unit including an image sensor for converting an optical image formed by a taking lens into an image signal, and said camera body including a power source, said camera system comprising: (A) said lens unit comprising: a lens-side voltage-measuring part for measuring a voltage of electric power supplied from said power source of said camera body via a mount contact provided on said mount; a lens-side memory for storing a lens-side threshold voltage, which guarantees an operation of said lens unit, in advance; a lens-side voltage-comparing part for comparing a measured voltage of said lens-side voltage-measuring part with said lens-side threshold voltage read out of said lens-side memory; and a lens-side communication part for sending a lens-side comparison result of said lens-side voltage-comparing part to said camera body via said mount contact, (B) said camera body comprising: a body-side communication part for receiving said lens-side comparison result sent from said lens-side communication part; and a display for showing said lens-side comparison result.