I can’t say I’ve ever gotten excited over a firmware upgrade, but then again, as a photographer who enjoys photographing architecture, I never thought I’d see the day I could correct keystone distortion—the distortion that makes buildings look like they’re falling over backward—in-camera and in real time with a Leica rangefinder camera. 2021 is only a couple of months old and already I have good feelings about it.
Leica’s latest firmware update, which enables a Perspective Control function, is currently limited to Leica M10 cameras (M10-P, M10-R, M10 Monochrom) and is easy to install. Simply download the firmware from Leica’s website onto a memory card, pop the card into your camera, set the menu to “Firmware,” and boom—your camera can now make the world stand up straight.
Keystone correction, or keystoning, is a constant challenge for architectural photographers. It occurs when the camera’s film plane (or sensor surface) goes out of parallel to walls or structures positioned perpendicular to level ground. There are two ways to address the problem: in-camera using tilt-shift lenses or a view camera, or post capture in Adobe Photoshop or Adobe Lightroom.
Correcting Distortion In-Camera, BLPCF (Before Leica’s Perspective Control Function)
Controlling perspective in-camera is the preferred, though slower method. To correct keystone distortion in-camera, you need a large view camera with tilt-shift movements. If you shoot with a DSLR or mirrorless camera, you’ll want to use tilt-shift lenses, which are available in a choice of focal lengths from OEM and third-party lens manufacturers.
About a decade ago, the Nikon D5000 had a perspective control function that enabled you to play back a picture on the camera’s LCD, manually correct keystone distortions with an on-screen slider, and save the corrected image as a separate new file. It worked quite well, but the feature soon disappeared on later models. Leica’s new firmware upgrade puts a new spin on an old photographic bugaboo.
Leica’s Solution to the Keystone Problem
When you engage Leica’s Perspective Control function (under Capture Assistants, in the camera menu), a white border appears along the edges of the LCD (and EVF) frame lines. As you tilt the camera up and down, the white border fluidly takes on a trapezoidal form, indicating the crop marks of the final image at that moment. If you’re working on a tripod, the frame lines remain steady. When handholding the camera, the frame lines change to counter the camera position in real time. If you do crop anything important from the final image, don’t blame the camera.
Leica’s perspective control feature only affects JPEGs. DNG (raw) files remain in their original form for post capture correction in Photoshop, Lightroom, or other photo editing software.
Keystone distortion can be corrected digitally, post-capture, in Adobe Photoshop, Lightroom, and other photo editing applications. The problem of making corrections post-capture is that inevitably part of the image has to be cropped to compensate for the distortion corrections and it’s often difficult to pre-visualize the final crop lines.
The beauty of Leica’s in-camera system is that you see the final crop marks live on the camera’s LCD (or EVF)—there aren’t any surprises. No longer will your heart sink when you realize way after the fact that the top of the building has to be decapitated if you want it to stand up straight. The crop lines react quickly to any changes in camera position, including horizon lines that go askew. To the best of my knowledge, this is a first among in-camera perspective control systems.
It’s important to note all perspective corrections are made to JPEGs only—DNG (raw) files remain untouched. DNG files must be manually corrected the old-fashioned way post capture in Photoshop, Lightroom, or other photo-editing software.
I’m a big proponent of using a tripod—even when photographing static subjects—but there are times and situations in which a tripod isn’t practical or even possible. The fact that Leica’s perspective control feature can be used handheld is an enormous bonus. I had a tripod with me while working on these photos and I didn’t take it out once. All of the accompanying photographs were taken handheld. Handholding a camera with a tilt-shift lens—or even a 4x5 field camera without a tripod—is possible but highly discouraged because you have zero certainty of level, distortion-free photographs. This is not the case with Leica’s solution to the problem.
Perspective Control with Any Focal Length Lens
Other than with larger-format view cameras, tilt-shift lenses are commonly used for architectural photography. The problem is that the vast majority of tilt-shift lenses are normal, wide, and ultra-wide-angle. If you need to shoot with a long focal length lens, you’re pretty much skunked.
As with all mirrorless cameras, Leica M10-series cameras aren’t limited by focal length. Even though Leica only makes lenses up to 135mm, M10 cameras have Live View, which means if you can adapt a lens—regardless of focal length—onto the camera via adapter, you can focus using the camera’s LCD or optional Leica Visoflex (Typ 020) electronic viewfinder.
One application that readily came into mind when using Leica’s perspective control feature is real estate photography. Unfortunately, many real estate shooters do not understand how to frame photographs taken in tight quarters with a wide-angle lens. The photographs can be dizzying, not to mention deceiving, in representing the true size of the rooms. Using an M10 with the latest firmware upgrade can bring much of this under control.
Everyday Applications of Leica’s Perspective Control Mode
Despite this story’s emphasis on architectural photography, in use I quickly found myself leaving the perspective control feature on even for casual shooting. However subtle as they may be, the distortions that make buildings appear as if they are toppling over are inherently part of any photograph you take the moment you tilt your camera up or down. You may not notice it, but it’s there, and it’s only when you have a white trapezoid fluidly re-cropping your photograph on the LCD as you aim your camera up and down do you realize how omnipresent these distortions are. This isn’t to say one should be publicly shamed for posting photographs with visible distortion on Instagram—it’s merely something to be aware of.
Since installing the upgrade to my camera, I find myself using the perspective control mode about 50% of the time, even when casually walking along the avenue, camera at the ready. It’s certainly not a feature you want on full time. For one, every time you aim the camera any place other than dead ahead, the cropping action automatically reduces the angle of view of the final image, and the farther you aim the camera up or down, the narrower the AoV becomes. Other than that, I find the corrective actions of Leica’s Perspective Control function to be an absolute plus.
Does the new Leica Perspective Control function interest you? If so, what kind of photography would you want to use it for? Let us know in the Comments section, below.