That is, indeed, the question.
Although formal registration is not required, several countries offer it; there are also a number of private companies offering registration. In the US, registration is required to bring an infringement lawsuit (without registration, disagreements can only be handled outside the court system).
The so-called "poor man's copyright," mailing the work to yourself and not opening it, is not a substitute for registration and is not recognized by the law, but it might make you feel a little safer.
In the most technical sense, no registration is required, but the further along you are in the process, the easier it will be to prove ownership.
Although works of sufficient originality are automatically protected by copyright as soon as they are "fixed," you may register the work if you choose. Registration will help prove ownership in cases of infringement.
Without formal registration, it is difficult to prove ownership; registration also makes it easier for potential users to identify and locate the rightsholder. In the US, registration is needed in order to take an infringement case to court, and allows additional awards in judgment.
Copyright exists as soon as you make a unique piece of work, even a photo of your family. Registration may help to prove your right.
Unfortunately, because formal registration is not required, it can be difficult to prove ownership of a work. When cases go to court, it often involves testimony from experts (literary critics, music theorists, etc.).
Someone else can take credit, benifits, rewards or ownership of your writings. It would be hard to prove other wise. Your word against theirs.
Because it does not include an examination process (as for patents), even a formal registration is not incontrovertible proof of copyright. The UK's IP office sums it up excellently:Note that neither registration nor sending a copy of the work to yourself show that you were the creator of the work. Keeping copies of all your drafts and any other material that shows your connection with the particular copyright material as you develop it could, however, be useful evidence if you ever have to prove that you are the author.
Copyright is automatically owned. 'Registering' a copyright simply adds it to a searchable database, which has several advantages like being able to prove ownership of the copyright in case of a dispute. However, a work is only public domain if the copyright owner specifically declares it as such.
Because copyright protection is automatic, it's safe to assume that any movie you encounter is protected unless you can prove otherwise. Neither registration nor notification is required.
Because it does not include an examination process (as for patents), even a formal registration is not incontrovertible proof of copyright. The UK's IP office sums it up excellently:Note that neither registration nor sending a copy of the work to yourself show that you were the creator of the work. Keeping copies of all your drafts and any other material that shows your connection with the particular copyright material as you develop it could, however, be useful evidence if you ever have to prove that you are the author.
Because it does not include an examination process (as for patents), even a formal registration is not incontrovertible proof of copyright. The UK's IP office sums it up excellently:Note that neither registration nor sending a copy of the work to yourself show that you were the creator of the work. Keeping copies of all your drafts and any other material that shows your connection with the particular copyright material as you develop it could, however, be useful evidence if you ever have to prove that you are the author.
Protection is automatic as soon as the work is "fixed" in a tangible medium (written down or recorded). You may contact the copyright office for formal registration if you wish; in the US, registration is $35 at this time.