User blog comment:LiamFrostveins/Elemental Manipulation/@comment-4536066-20130115160158

Same rules as always. A mage can handle an element to any extent allowed by the magic they have pooled via charging (or whatever) and the control that their experience handling magic allows.

Whether changing the chemical state of a pool of water into steam is an easy process (because it's a batch, low-detail action) or a difficult one (because it's a very large, high-energy change on the subatomic level) is subjective.