Paintshop Photo Pro: Correcting Perspective

PaintShop Photo Pro is a professional image editing program that is affordable. Take your photos and apply effects and other edits. With the pro version, it is possible to create cards, slideshows, photo books, collages and calendars. One such useful tool is the perspective correction. It can deal with images in which the perspective may have problems, such as leaning buildings.

Leaning Images

Perspective correction is needed for when objects are out of perspective. This frequently occurs with tall buildings. Many times, it will look like the building is leaning because the camera did not use the correct focal length or angle of view. This type of perspective issue is a problem when looking up at tall objects or with objects that have specific dominant shapers or vertical lines. This type of distortion occurs because the cameras sensor is not parallel to the surface of the object. When the camera is not parallel, the vertical lines will bend inward. Normally wide angle lenses will accentuate this perspective distortion.

Common Scenes with Distortion

There are several types of photographs in which perspective correction is frequently needed--in particular, outdoor photos that contain fence posts, telephone poles and slanted trees. Other photos include indoor pictures that may have skewed furniture and tilted wall. The last types of photos that have issues are architectural pictures that contain structures and leaning buildings. Many times the perspective issues cannot be avoided. In several instances, this type of distortion can be used for dramatic effect and is desired.

How Correction Works

The perspective correction will take all the vertical lines and alter them so that they appear as if they would in real life. It will also make the parallel lines cross all at one point. Paintshop will automatically correct for this without degrading the photo. Ultimately, the top of the photo corrects the perspective as the photo is stretched out at the top. The vertical length also needs to be stretched as well as just stretching the top will make the photo appear squat. Perspective transformation tools will calculate exactly how much the photo needs to be stretched.

Resolution

An issue that can occur with this type of photo transformation is that resolution can be lost. Paintshop makes it possible to use different mathematics depending on the lens used, as each lens will have different characteristics. Ultimately lower resolution occurs when the original picture had a low image resolution and how much the photo needs to be manipulated. More manipulation and stretching will decrease the resolution. There is a tradeoff between high quality details and perspective correction. 

Correction Tool

Paint shop makes it possible to control the amount of stretching that occurs to correct the perspective. It uses a grid that will be aligned to the image that needs to be straightened out. The image can also be cropped or uncropped. Many times, professional photographers will leave a little bit of perspective distortion as the natural eye expects this. A perfect perspective may look a little off due to this expectation. Undo the correction and redo it until the desired picture is created. It may take a few tries to get a hang of the perspective correction tool.