Your collection of previous work—reels, showreels, completed projects. The first thing a producer or network sees before hiring you.
Your portfolio is the calling card that enters the room before you do. Before a producer, a network, or a production designer invites you for an interview, they look at what you've done — and literally in the first two minutes. This isn't marketing, it's proof of craft. A good portfolio doesn't show your favorite scenes, but your ability to deliver under real conditions.
On set, your portfolio becomes relevant when it comes to casting. A DoP with a strong reel will be hired faster than one without. An editor whose cutting examples show they understand pacing and feel storytelling in rhythm will be preferred. The portfolio eliminates conversations about skills — it demonstrates them. That's the difference. You need your most important projects in it: feature films, if possible; TV work that shows high production values; and at least one project that documents your own creativity, not just your execution of others' visions. A cinematographer's showreel should show in 90 seconds: lighting design, camera movement, color grading, and how they handle different genres.
In practice: Your portfolio must be current. Projects from five years ago should be removed, unless they were exceptional and demonstrate something fundamental that you still need today. Many producers scroll through your portfolio online — this means the best material should be at the front. Not chronological. Not sentimental. The strongest first. If you have to choose between a large project with mediocre work from you and a smaller project with brilliant work, take the smaller one. A well-thought-out editing sequence from you weighs more than your name in the credits of a big film where you were an assistant.
A portfolio also protects against speculation. If someone says you could fulfill a certain task — your portfolio should answer that before negotiations begin. At the same time, a portfolio is not static. You add to it, you curate upwards, you drop weak material. This is your professional development, documented.