The olive hasn’t much to do with photography other than that olive groves end up being in a lot of landscapes. However, olive oil is one of the good things of Italy that most people appreciate while here – Orvieto olive oil is one of the world’s best.
And then comes the marketing, and there lies the rub. The European Union is almost criminally lax when it comes to how olive oil can be described on the label of a bottle. Sadly one can almost ignore the (mis)nomen of Extra Virgin, much better to look for DOP on Italian oil which stands for Denominazione d’origine protetta which ensures the oil comes from a specific area and therefore not blended.
Green oil lasts longer too – up to a year if stored in a cool place in a dark bottle or tin. That said the yellow variety is good too and better in some ways – if you can trust where it comes from. Made from maturer darker olives, yellow oil is sweeter, just as full of flavour but lasts less long as it has less anti-oxidents than the green fruit. Most oil, even the best, tends towards the yellow because the mature olive gives more oil and therefore a better crop. But be warned, yellow oil in a shop could be blended or refined.