'Photographer' as such is not a protected vocation in any way in my country. Anyone can be a 'photographer'. Whether you earn money or not defines your relationship to the authorities. As soon as you run a registered company and pay VAT, you are classified as 'professional' business and follow specific taxation rules, amongst which in particular important are deprecation of investments over several years and full deduction of business expenses. When you are not considered as a business professional, you are by definition doing 'photography' as a hobby and thus cannot deduct expenses except under very limited situations. The breaking point is when you are eligible for VAT registration, which equals an earning of at least NOK 50.000 over a 12-month period (in fact, registration then is mandatory). You do need to be registered to invoice clients. Otherwise, the payment is considered a salary and the taxation rules are very different from what applies to a business.