This image from my residency at Guildford Cathedral won the British Institute of Professional Photography regional print competition in the Architecture Category. It's a double image, with ultra-wide angle (12mm full frame) rectangular images from the same viewpoint, arranged in a cruciform shape - hence the dark corners.
Aligning the image in Photoshop was a difficult task - the auto align feature would not accommodate the different aspect ratios, so all had to be done manually. On site, it was necessary to place the camera very precisely, and also very low to obtain the maximum distance from the object. As the Canon 6D screen is not hinged, the only way to see what was on the it was to use a compact mirror.
The photos below show the set-up as well as the final image.