Especially when you're including architecture in your shots, there are times when the combination of the angle you are pointing your camera and where your point of focus is, leave you with an image Where all the vertical lines slope into your composition. Sometimes you want this effect to be pronounced and at other times it would be nice to be able to compensate against the effect.
If your main job is doing architectural shoots you may have already invested in some high quality, tilt-shift lenses. If you're a Nikon shooter like me, you can purchase a very nice Nikon lens for just over $2000.00. If you have the latest versions of Photoshop or Lightroom CS, they include a function to assist you in fixing converging lines in your photos. But you can also do a simple fix to your photos manually in earlier versions of photoshop that you may already be running.
|Before fixing the verticals and after|
In the video below I walk you through one method that I use. My voice was starting to go when I recorded this but you should still be able to easily hear my comments.