Photoshop's lens correction filter or the respective Bridge feature are often not good enough in correcting the geometrical distortions associated with using wide-angle or fisheye lenses. In Photoshop CS6, Adobe introduced the Adaptive Wide Angle filter which can prove very useful & intuitive. Let's check how it works.
Decompress the tutorial photo and load it in Photoshop CS6.
Before editing the photo, do something simple yet fundamental to non-destructive editing: convert the background layer into a smart object: Go to the layers panel, right click the background layer and select "Convert to Smart Object". Photoshop will retain the original pixels into the smart object layer. All your edits with the Adaptive Wide Angle will be saved into a "smart filter" which you can double click any time and re-work your settings.
On the upper right of the filter window there are a number of settings associated with the way Photoshop applies the geometrical corrections. Photoshop will analyze the photo file and automatically select the best type of correction. The Auto mode usually works very well. Below these settings you can see a preview window that lets you place the constraints more accurately.
Repeat the above steps to straighten the roof.
TIP: Holding down the Shift key while dragging will automatically assign the horizontal (or vertical) attribute to your constraint.
Repeat the same steps to straighten the other columns and the walls. If necessary click and rotate the marks on the circles to fine tune the constraints:
Select the Magic Wand Tool (press W). Hold down Shift and click inside each transparent area.
Choose : Select > Modify > Expand from the main menu, enter 3 pixels and hit OK.
Press Shift and F5, to invoke the Fill menu. Click on "Use" and select "Content-Aware". Hit OK.
Compare the photo before and after applying the Adaptive Wide Angle filter:
With regards to the "Lens Corrections" available in Adobe Camera Raw (or in Lightroom):