After arriving in Iran, you should get a Customs Declaration Form which is available in the customs hall, fill it out with the required information, and hand it over to the customs evaluating inspectors.
The following articles are considered as the necessary items of the tourists, hence permitted to be imported and exported without being subject to any custom duties:

• Personal jewelry
• One camera
• One non professional video or filming camera and portable video equipments
• A pair of binoculars
• A portable musical instrument
• A portable radio recorder
• A portable personal computer
• First aids kit
• A camping tent with its accessories
• Sports wears such as fishing tools, excursion boat smaller that 5.5 meters long, ski boards, tennis rackets, mountain climbing equipments, diving articles, bicycle, golf articles and similar items
• Baby carriage
• wheelchair for disabled persons