Architectural photography is a highly disciplined area that requires patience, a keen eye, and—very often—the use of a perspective control lens. These lenses have a special mechanism that allows the photographer to raise the center axis of the optic, which in turn counter-balances any distortion in an image, such as converging parallels. “PC lenses” as they are known are very expensive and quite tricky to use, perhaps beyond the scope of the enthusiast photographer’s budget.
Fortunately, there is a tool in Photoshop that allows us to mimic not only the effect of a PC lens, but also to counter the in built-in distortions that all lenses have. Simply called Lens Correction, it is found under the Filters item in the Photoshop menu.
For this article, we are going to use this image:
The original image
It was shot with the camera pointing slightly upwards. Hence the converging verticals; the appearance that the walls and trees are falling into the center of the image. There is also some minor lens distortion that manifests itself in a curvature of the walls.
Let’s go ahead and open the Lens Correction tool.
The lens correct tool
As you can see, it appears as a large window, not unlike the Adobe RAW tool. The first thing we should do to help us work with the tool is to switch on a grid. This can be done from the checkbox on the bottom left. To the right, by default, Lens Correction opens with the Auto Correction tools tab. You can choose to correct, geometric distortion, chromatic aberration and vignette. If you are using a high-end lens, you may find you only need to check the geometric distortion box. With less-expensive lenses, you may have to correct all three.
Previewing a grid
Below this, you will see a list of camera manufacturers, models and lenses. There is quite an extensive database, and the tool will attempt to work out what your camera/lens combination was. However, if it does not find your equipment automatically, you can manually enter the manufacturer of your camera, the model and the lens. If your equipment is not on the list, there is a handy search function that will allow you to look for third-party versions.
Once you have found your combination, the Lens Correction tool will automatically correct the distortions that you have selected above. You should see a visible effect on the image as the corrections are applied.
Camera and lens combinations
To remove the converging parallels and carry out further adjustments to lens distortions, we can go to the manual modes. This is accessed by clicking the Custom tab next to Auto Correction at the top right of the window. It gives us access to a range of tools, including the ability to correct chromatic aberration in all three color combinations, and fine tune the geometric distortions. However, for most equipment combinations, the auto settings will work fine, so we are going to use the transform tools at the bottom.
The main tool that we need is the Vertical Perspective tool. To bring the verticals back to a more upright position, we need to slide this tool to the left. With our grid overlay on, we can judge exactly when the walls of the building are straight, which in this case is at -41.
We can also make some corrections to the horizontal perspective if required. Problems with horizontal perspective are more likely when shooting straight onto a building, but when the camera is not quite parallel to the front wall of that building.
You can also correct any issues with the horizon by using the Angle tool or, for more accuracy, the Straighten Tool found on the top left of the main window. To use this, click and draw a line along an area of the image that should be perfectly level.
When using these tools, you should be aware that Photoshop will automatically crop into the image to make corrections. Therefore, you should choose images that have a reasonable degree of space around them to counteract that cropping effect. Once happy with your corrections, click OK and you will be returned to the main Photoshop interface.
The final result
Like many tools in Photoshop, Lens Correction is very useful, but it needs the right image to work well. If you are planning a professional architectural shoot, then you may be better off hiring a PC lens. However, for general correction of converging verticals and for distortions within the lens, this tool is an excellent way to improve the look of your images.