Correcting Perspective in Architectural Photos

This month’s theme at our local camera club has been Architecture.  One of the most common issues in shooting pictures of buildings, especially tall buildings is how they seem to lean back away from the camera, and how the sides of buildings all seem to tilt inwards.  Well, it is a little known fact that buildings tend to be camera shy and don’t like having their photos taken.  Actually, the effect is caused by the difference between how cameras process and how our brains automatically make corrections.   When you tilt your camera backwards to get the entire building in frame, the light is no longer hitting your camera at a parallel angle.  When the camera and computer go to process the image, it thinks that the top part of your picture is farther away, hence it looks like it is tilted away. Luckily for us there are some basic techniques to fix this, both in camera and in post-processing.  In camera, the easiest way to get true vertical buildings is to keep backing up until the lines really are parallel.  Unfortunately, on most city streets this is just not practical.  A second way is to focus in on some architectural detail, which can serve to suggest the entire structure.  Again, that often does not convey the impact of capturing an impressive building.  The last way in camera is to buy an expensive Tilt-shift lens.  These lenses allow you to change the plane of the subject to match the backplane of your camera.  All you need for this is money.

Fortunately, the tools available now in both Lightroom and Photoshop have made the process much easier.  For any of these techniques, the first step is to make sure you have enabled the Lens Correction checkbox as part of your import preset.  Your camera can tell your computer a lot of things that will automatically handle a lot of distortion. We have discussed this before, so I am not going to cover that again right now.  In LR, the next step is to get your horizon level.  In the develop module, select the Crop overlay and either use the handles on the grid or drag the ruler from the Angle window across the line you want to be horizontal.  Now it is time to go back down to the Lens Correction panel and select the Manual tab.  This will give you access to sliders which allow more detailed Distortion, Vertical, and Horizontal control.  In LR 4 and earlier, this part of fixing the picture is up to you.  You have to make adjustments until the lines are vertical enough.  One of the unfortunate side effects of this can be seen here.  The keystoning of the image means that you may have to recrop the photo to remove the gray areas.  Or of course you can use content aware fill over in Photoshop.  In the new LR5 Beta, they have introduced a new choice in the Lens Correction panel.  It is called Upright and is found under the new Basic Tab.  The video shows its power far better than I.  http://www.youtube.com/watch?v=x4-V2hLgf7Q

Having your buildings stand up straight and proud is part of what sets snapshots apart from photographs.  People will notice they are better, but won’t always recognize why.