My Sea Is Dripping? Photoshop To The Rescue

Horizon Allot of times you’ll look at two very similar pictures, and say "Man, the left picture looks great, the right one is nice, but the left – Man I love it". Eight times out of ten, this difference can be explained by something called rules of composition. There are many such rules, (The Rule of Thirds is one known example, but there are many more). The rules of composition are a set of thumb rules to help the photographer rely on experience gathers in many years of art. (I was trying to avoid the whole "breaking the rules" argument, but feel free to comment) One such rule simply says Keep Your Horizon Straight. It’s a simple rule to follow, just make sure your camera is leveled when you take the shot. If you miss that rule, you’ll sometime hear comments about people falling to the side, or having the sea spilled out of the frame – some persons can not resist this remark. Some of the new DSLR models can help you with this task. Nikon’s D80 (or Nikon’s D70) for example can display a grid on the view finder, and you just need to make sure the horizon aligns with that line. There are also some nifty accessories you can attach to your hot shoe mount if you have one, see this nice gizmo from Hakuba for example.

But leveling the horizon can be sometimes tricky. When you take lots of shot, when you don’t have time to aim well or when you don’t have anything to level against.

There are two solutions for this problem:

the first is practice: go to the beach on a sunny day and just take tone of horizon pictures, after some practice, you will find out that your shots are getting more and more leveled. (If anyone asks you why you have 12,000 shots of empty sea on your card, just tell them you thought you saw Nessy – the Loch Ness monster)
The second solution involves some Photoshop work. And here is my guide – Un-tilting The Horizon in Six Simple Steps:

Lets start with this picture – obviously tilted. So tilted in fact that it did get the "if you don’t watch it all the sea is going to spill of the right" remark. (you can click this or any of the images to get to a larger flickr image)

Once you have this image loaded in Photoshop, the first step is select the Measure tool. You can do this by clicking and holding the eyedropper tool or by clicking "shift+I" a few times. See the picture below.

The next step is to click anywhere on the horizon, and draw a line using the measure tool. Make sure your line overlaps the horizon. There is not need to cover the entire horizon with this line, but from my experience, the longer your line is the more accurate the results.

The next step is to select the Image -> Rotate Canvas -> Arbitrary command from the menu.

Notice the pop up you get, surprisingly it has the same value as the measure tool info window. This pop up is just begging for you to OK it.

Once you OK this pop up, your image will be magically rotated into a nice leveled position. Alas, you will now have some spare canvas on the sides of your image. I like to crop this using the crop tool. I set the ratio to 2-3, just like the original image had. I then set two guides (you can do this by dragging the white ruler at the top/side) to show me where to start the crop.