Glossary
By default, the creator who shoots and edits a piece of content owns the copyright in it, even after a brand has paid to feature in it — unless the contract explicitly assigns or licenses those rights to the brand instead. This is general practice, not advice for a specific contract; a lawyer should review the actual agreement for anything high-value or unusual.
Ownership (who holds the copyright) is a separate question from usage rights (what the brand is allowed to do with the content — repost it organically, run it as a paid ad, use it indefinitely across other channels). A brand can pay for broad usage rights without ever taking ownership of the underlying file.