When you ask or commission another person or organisation to create a copyright work for you, the first legal owner of copyright is the person or organisation that created the work and not you the commissioner, unless you otherwise agree it in writing.
However, in some circumstances, for example when copyright is not dealt with in the contract to commission the work, Courts may be willing to find that there is an implied licence from the contractor to the commissioner so that the commissioner is able to use that work for the purpose for which it was commissioned. This does not necessarily result in a transfer of ownership. Instead, the company commissioning the work may only get a limited non-exclusive licence. This situation demonstrates the importance of establishing who owns copyright through a contract.
Prior to 1 August 1989 though, the copyright in photographs, portraits and engravings (and only those types of work) which were created as a result of a commission were owned by the commissioner and NOT the creator. Therefore at that time, if you commissioned someone to take photographs for you for instance of your wedding party, then you would be the owner of the copyright in those photographs. The commission though must have been undertaken for money or money’s worth that is equivalent goods or services.