From what I understand about copyright for intellectual property (IP), there is no need to file for it. It is automatically assigned to the creator. i.e. You can choose to take action against anyone who uses your images/literature without your permission. You'd have to take the person to court to get any compensation and this varies according to the 'loss' you have incurred as a result of others using your creation without your permission. Also you'd have to be able to prove ownership of that creation e.g. original copies or drafts, manuscripts, etc.
You can file for copyright/patent too, i.e. that means you go through the long process of proving your ownership first, so that in the event that someone infringes on your ownership, you can claim for damages more easily.
Copyright is just to say that the image or artwork is yours. Being a professional photographer, I choose not to copyright my work. You are free to use any of my images and I will be very honored. No lawsuit. (do keep in mind that lawsuits are just to benefit lawyers and courts)
FYI, I do not use others but allows others to use mine.
Under the Berne Convention on Copyright 1971 and the Digital Millenium Act a photographer is automatically granted copyright on his or her work the moment you press the shutter. The only exception is when you have been comissioned to take photographs by someone who pays you, as you are then technically an employee.
If i am not wrong in Singapore copyright is already automatic. Dont need to actually have the name there. As long as someone uses it without your consent, you can actually take some legal action.
To be sure wat you can do is just make a copy of everything you have done in a CD or anything, and send it by post to yourself. Dont open it and just keep it aside, until if some time you need to prove tat the work was originally yours, you can show them the letter with the original contents.