Using perspective and skew in Photoshop.

Left:  Church before correction    Right: Church after correction

Have a look at the above images.  The exposures are one and the same.  The difference between them occurs after the file has been accessed by photoshop.  What are the differences, why do they matter, and how did I do them?

The image was taken off center, mostly because it was a better position to shoot from and I captured more of the flowers on the left side of the door (you can see them if you look carefully).  Shooting it off center caused the roof line to appear at an angle.  I used the skew command in Photoshop to line this up parallel to the top of the frame.

With height comes a reduction in the width of any building, which is why the church's tower is smaller at the bottom than the top.  This is the normal effect of perspective.  You can use a PC (perspective control) lens to correct it in camera, or use a bellows with the ability to angle the lens; something present on some large format cameras.  My solution was much more economical.  Use the perspective control in Photoshop to widen the top of the image.  It worked fine.

The problem this produces though is that it makes the church appear squat because now the width is the same all the way up but the height is wrong for the proportions.  For this I used the distortion command and lengthened the whole image, stretching the church.  The downside to this is that everything gets stretched, not just the upper part of the church.  If there was a way to stretch the image proportionally, with none at the bottom and an increasing amount over the height of the image, the effect would be much better.  However, it works well for the most part.  This is why the image on the left is shorter than the image on the right.

Finally, there was the issue of the missing corner.  When the skew command was issued the upper right part of the image became barren as no image data was available for it.  Fortunately, the missing section was only sky and it was a simple matter of using the clone tool to patch up that part of the photo.  I think the corrected version looks much better than the original.  What is your opinion?