Image Copyright

[susanxx]

I am a little confused by copyright law as I have been told by a photographer that the copyright law was brought into being during the 1940/50's and does not have a time period of expiry. There was no copyright prior to 1945 at least, thus anything prior to that date can be used without infringement. However on reading the web page regarding copyright, it appears that it only lasts for 50 years from the date on which it was published! Any help to decipher this confusion please?