In the US, you automatically own the copyright to photos you take unless you’ve signed it away. Simply giving the band the files does not transfer copyright.

What you need is a written usage license/agreement, not just a copyright notice. The agreement should say:

• you retain copyright
• the band is granted limited permission to use the images for specific promotional purposes
• the license is non-transferable
• any other use requires your permission
• credit is required if that matters to you
• optionally, a time limit or other restrictions

That helps prevent a record label or other third party from legally reusing the photos under the band’s permission alone.

Adding a copyright notice can help communicate ownership, but it does not replace a license. You can also register your photos with the Library of Congress to formally register the copyright, which can strengthen your legal position.

If you want real protection, especially if the images might become commercially valuable, have a local lawyer help draft a simple license agreement.