Treat it professionally from the start. If photography is not part of your formal job, a per-shoot arrangement is usually cleaner than a salary change, which could imply a broader ongoing photography role and possibly a job description update.

Check your employment contract carefully: many employers claim ownership of work created during employment or on company time, including photos. If you want to use the images in your own portfolio or promotion, that should be explicitly agreed in writing.

For portraits, get model releases from the people being photographed, especially if the images will be used for marketing or promotional purposes. Releases should clearly state where the photos may be used and can include limits on personal promotional use.

Also clarify expectations up front: scope of each shoot, how many sessions/images, whether future shoots are separately paid, and what the company may do with the images. Even if the fee is modest, having a simple written agreement covering pay, ownership, and permitted use helps avoid misunderstandings later.