When you photograph a tall façade from below, its vertical edges converge toward the top. This follows from perspective with a tilted camera rather than necessarily indicating a defective lens. Digital correction can make those lines parallel, but it changes image geometry and needs space that a tightly framed photograph may not provide.
Separate three different appearances
A camera rolled sideways tilts the whole picture. A camera pointed upward produces converging verticals. Barrel lens distortion instead curves lines that are actually straight. These appearances can occur together but require different adjustments. Do not start with extreme perspective controls when a small rotation is all that is needed.
An appropriate lens correction may straighten curved edges first, making perspective easier to judge. Use the profile that genuinely matches the lens if the application provides one. An arbitrary profile can make matters worse.
Mark two reliable verticals
Choose building edges that are genuinely vertical and reasonably far apart. Place the guides carefully along them. A sloping extension, leaning pole or irregular tree edge is an unsuitable reference. Afterwards, check windows, doors and people for plausible proportions.
A completely parallel façade can look unnaturally stretched when photographed from a very low viewpoint. Removing every trace of convergence is not always necessary. A moderate correction may clarify the architecture without denying the original upward view.
Work on a façade with little spare framing
Suppose the roof peak sits only a few pixels below the top edge. Fully correcting converging verticals stretches the upper building and automatic cropping removes the peak. First disable the crop constraint to reveal empty regions. Then reduce vertical correction and compare the point at which both roof and plausible proportions survive.
Slight remaining convergence may be more convincing than a perfectly upright but clipped façade. If an objectively parallel representation is essential, the existing capture may be insufficient. Another viewpoint or photograph is then the cleaner solution. Artificially extended sky can fill empty corners but cannot supply a missing genuine roof structure.
Inspect the lower third after transformation as well. Pavement may appear too broad, people near the edges may stretch and a circular sign may become oval. An aspect adjustment should not merely hide these effects in one area. Compare the entire building and decide whether the geometric improvement justifies the reshaping.
Inspect empty areas and lost detail
Transformation often creates empty image regions. An automatic crop hides them but may remove roof edges or foreground. Temporarily disable the crop constraint to see which area is being lost. Then balance crop and correction strength together.
Heavily stretched upper regions must be resampled from existing pixels. Fine façade patterns may look softer there than near the bottom. Check the actual output size rather than only a small preview. For future captures, more distance, a higher viewpoint or less camera tilt can help where the location permits.
