Raised Light Fixtures

[Danf310]

So I've been looking at planted aquariums and more and more I see tanks with raised light fixtures a few inches above the tank.

My question is why is this and what advantages (I'm assuming there are advantages) there are to raising the fixture?

 

[blert]

The biggest advantage is the ability to raise and lower the fixture to adjust intensity. They can also be easily raised for maintenance reasons.