it is the journal not the field (Score 2, Interesting)

Policy on copyright does differ from field to field, but it is more a matter of the journal than the field. Some journals have enlightened practices, some do not. For example, the Royal Society, which is the UK equivalent of the publisher of Physical Review Letters, has a very enlightened policy, and lets you publish under a creative commons license and retain copyright. The American Physical Society has a far more outdated policy, which looks like it will finally change.