Art

This often throws me on a shot like this. The strong diagonal lines can often mislead you when taking such a shot. I find it best to look at the scene first without the camera and fix upon something that I know is level. In this example the arch over the water is obviously meant to be a level horizon. If you then look at the focus sensor lights in your viewfinder (I have nine in the 30D)you can line up the top of the building with the middle row of sensors, or the top/bottom row if you need a different composition. That should give you a perfectly level shot.

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