Today’s Question: As a follow-up to your answer about nudging the rotation of an image to straighten a horizon, how do you deal with a situation where lines in a scene make it appear there is a crooked horizon even when the image is perfectly level? For example, the shoreline of the opposite side of a lake might appear to slope upward from left to right, even though the camera was completely level.
Tim’s Quick Answer: Ultimately, I recommend rotating so the image looks as correct and natural as possible, even if that means that a line that could be mistaken for a horizon is not perfectly horizontal.
More Detail: When it comes to rotating an image by an arbitrary number of degrees, to me the ultimate goal is for the image to look natural, or to not appear to the viewer to be crooked. This can sometimes be difficult to accomplish, such as when there are lines in the scene that trick the eye into seeming like a horizon that isn’t straight.
If there are elements within the scene that should be perfectly vertical, such as buildings or a flagpole, you can use those as a reference for rotation. If those elements are easy to see in the photo, it can be more important for them to be straight than for a “false horizon” to be made horizontal.
In some cases, you may find that leveling the image based on gravity (such as by using an in-camera leveling feature) results in an image that appears to have a crooked horizon. But then when you rotate the image so the fake horizon is perfectly horizontal, that looks wrong too. In this type of situation I’ll compromise, rotating somewhere in between, trying to strike a balance that looks best overall.
Ultimately what generally matters most is how the image is perceived, regardless of which lines may or may not appear perfectly horizontal or vertical. Therefore, I recommend evaluating the image based on what looks most natural, even if there are crooked lines. It can also be helpful to get input from other people, so you have more of a consensus about what looks best for a particular image.
