When you take a photo of a real estate scene that has straight lines, such as a room interior or walls in a property exterior, you may find that those lines appear crooked or curved in your final photograph.
This can affect both horizontal or vertical lines, and they may appear to be sloping or bending inwards or outwards. Sometimes, the lines might even look straight when you preview them in the camera, but come out curved in the final photo.
There are a few things that can cause these kinds of distortion, such as the lens you used, perspective distortion, or the angle you shot the photo at. With a few quick tips though, it is easy to mitigate this and get straighter lines.
If you're shooting in RAW, the lens you are using for shooting real estate interiors is likely making straight lines bend outward from the middle, like a barrel.
The wider your lens is, the more likely this is to happen. This is just the nature of the way the glass in the lens works.
If you preview the shot in the camera, you may not see this distortion, because the camera is correcting it for you in the preview. But the saved RAW photo has none of these corrections.
The good news is this can typically be corrected with photo editing software, and the correction is often done automatically when you load the image.
If you shoot JPEG files, this lens correction is automatically applied by the camera, and saved in the final image, so there is no need to worry about it in this case.
When you look at a tall building when you're standing on the ground, you have probably noticed that the top looks smaller than the bottom. This is an example of perspective distortion.
Things that are further away look smaller than those which are nearer. Because of how cameras work, this kind of effect can be particularly pronounced in photos, especially when photographing real estate interiors, even when the difference in distance is fairly small.
The best way to minimize sloping lines is to keep the camera level and shoot as straight as possible. A good tripod with a spirit level is a great tool for this.
If you need to photograph a room from higher up, resist the urge to point the camera upwards or downwards from where it is. Instead, move the camera itself higher or lower, and keep it pointing straight ahead.
Sometimes the situation calls for having to adjust the angle of the camera though, perhaps to avoid getting too much of the floor or ceiling in the photo.
In this case, you're likely to get distortion, but it can generally still be fixed in editing. This does result in some of the edges of the photo being cut off, so make sure you take a wider shot than what you need in these cases.
If your photo is a bit off, such as having a non-level horizon or crooked vertical lines, you can use Photomatix Pro's Straighten tool to make adjustments.
The Straighten tool is available on the Finishing Touch panel that appears after you create the HDR image. The tool allows you to correct a non-level horizon line, and vertical lines that are not quite vertical, with sliders to adjust the horizontal and vertical perspective, as well as rotation.