All copyright applies to work created by their originators. Examples of such work can include a photograph, a story or any text published work like the lyrics to a song, articles like this one or a digital file. It does not apply to something that is just a thought, like when you think of something, copyright does not exist as yet. Now when you reduced your idea into a material form then only will you be the person that is holding the rights to that work. Even if you tell your ideas to someone else, and that someone reduce your idea into a material form, then that person will be the holder of the rights to that work. For example, you may tell a photographer that you want a photo taken in a certain manner, angle, etc, but ultimately, the photographer using your idea of the photo will be the owner of the photo. The person who holds the rights to an image is therefore its creator, and does not need to be the person responsible for pressing the shutter release on the camera specifically, but rather the person responsible for the artistic input, which includes styling, lighting, sets and composition.
The South African law differs from international as far as the “commissioned photographs” is concerned. Normally this will come to a freelance photographers may have no rights to their work, but fortunately this issue can be circumvented by a mutual agreement even when it takes the form of a verbal agreement. The act allows for negotiation of these default terms, and consequently any agreement negotiated will then fall under contract law which then overrides the Copyright Law.
Copyright is an automatic right, there is no need to take any action to ensure your photograph is protected by the law. A copyright mark on a photo is only a reminder that the photo has copyright on it and can help to let people know who is the photographer that holds the copyright. You may want to include your name, the year the image was first made public or was published, the copyright symbol and which rights are reserved. (These can include all rights being reserved or commercial use, uses other than for educational purposes, print and publication more than a single form of media etc.)
Another fact to know is that copyright is valid for 50 years from when an image or anything else where copyright is applicable to was made public or the first date of publication. That publication date is the most important measure to establish the originality of any work, and where it comes from. Your work also does not need to be presented to the public to establish your copyright in it.