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.
Tripods Optional
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.
11 Comments
As an architect I have been concerned with perspective control for decades and have explored most options. (I’m currently using an M240-M which won’t have this function.) Nevertheless, my feeling is the autocorrection over corrects. Our brain compensates in real time but when implemented in the fixed image it seems artificial. Having said that, uncorrected is also distracting. So, my solution is a modest adjustment. I utilize a greater wide angle than needed (often in portrait mode for a landscape shot) keeping it close to horizontal; later cropping the foreground (often asphalt) and some of the sky. There’s also an opportunity for a modest correction according to the photographers judgement. This is more plausible now with high-res sensors and ultra-sharp lenses. All doable in post, of course, but much more satisfying in-camera for some.
Points of contention:
1. The perspective control is questionably useful via a tiny back screen on a camera. You can do it in Photoshop generically on your huge monitor, and when you do your find the big monitor is necessary to finesse the details. I cannot imagine getting it perfectly right on a camera back.
2. Huge ironic negative seems to me about a Leica Monochrom is it's big feature: luminance only recording. It's completely unlikely these files can do B&W as well as can be done using an RGB file & color channel tools in Photoshop. This is obvious if you think about it: you always have more options with more data. RGB files have triple the data. I'd like to see this point addressed by a Rep as it's really a deal killer for creative B&W editing. The argument could be, keep it simple, but I suspect it's more about devotion to whatever Leica gives you as the best thing. It's not.
3. Upside may be less noise, faster operation, etc. May be, but those are not my points. And I am sure it is a jewel in build quality, again not my point.
~~~ Supporting points ~~~
As example, when I create B&W landscape in Photoshop I apply the luminance values captured only by the red channel to the sky area. This dramatically separates blue sky from white clouds. As a test as I wrote this, I downloaded a Monochrom file to examine in Photoshop, it has only grey channel. Because you don't get RGB files, you can't create B&W with emphasis on any one channel. It's a failed idea for B&W image creators.
I would note that old school B&W silver film was panchromatic in sensitivity ie equivalent to an RGB sensor. Because of this you could put yellow or red filters in front of the lens (ala Ansel Adams) for better distinction of blue sky vs white clouds, a green filter for other tasks, ect.
I love to be proved wrong, so if BH can knock me out here, please do. It will only add to what I know about editing.
Is it me, or does this feature make the images look really "wonky?" I'm not going to overtly advocate for purchasing tilt-shift lenses over this method, I know a lot of people like keystone corrections as a quick fix without the investment into the expensive glass. But, the rotating and stretching of the images to solve converging lines just always results in off-kilter-looking images. I know the images in the article were just a quick example, but if you're going to take the time to plan your shoot or spend this much money on a camera and its lenses and spend any considerable amount of time or money on travel, and then carefully compose a shot and consider all of the parallaxes, maybe a firmware-enabled, quick-fix isn't the desired method in finishing your shot?? Sure, this all could be labeled as "pretty cool," but in terms of results, it's a little gimmicky. I'm more interested in the development of a manually controlled sensor-shift technology that allows for shifting the rear standard, as it were, keeping the lens in a fixed position, maintaining subject-to-subject relationships when composing one shot, or even a panorama in-camera. This would be an enhancement worth the investment.
Joseph,
"a manually controlled sensor-shift technology that allows for shifting the rear standard ... keeping the lens in a fixed position, maintaining subject-to-subject relationships when composing one shot, or even a panorama in-camera"
I'm in with you on this one. Never mind keeping the dust off the sensor, have any idea how much this camera would cost to design and build?
As for the 'wonky' part of the equation, yes - but I can find varying elements of 'wonkiness' in comparable photographs captured using tilt-shift lenses, full-tilt view cameras, and images corrected in Photoshop. It's unavoidable when trying to translate a 3-D reality into a 2-D space.
And while I wholeheartedly believe you get better image quality when you correct distortion optically as opposed to digitally, the idea you can get similar results shooting from the hip as you can mounted on a tripod - which for the record is my preferred method, is pretty darn impressive.
All that said, you have to agree the results are impressive regardless of how they came about.
Software tilting the keystoned image, or a tilting lens or focus plain, you'd get the same impression. I know, I have both the T/S lenses and the software (a standard feature of Photoshop).
The other method is to prevent keystoning from the start with rise/fall. This cannot be done in software because it would involve creating data that is not there. This is of course, when squared up to the desired image; raising (or dropping) the lens so that an area of the image circle projected by the lens not yet on the sensor falls on the sensor. Rise adds to the upper part of the view because an image circle in the camera is projected upside down. When that is done in camera, the projection is lengthened, and although the lines look good, the image is longer toward the edges. This is actually useful to enhance near-far compositions in the landscape.
BTW, re dng's, the correction is in fact applied to dng's in the following way: If the image is obtained in live view mode, and one uses adobe camera raw, the geometry correction is automatically applied via the guides selection in adobe camera raw, You can turn it off, or adjust as you wish in acr geometry panel. If the image is obtained when live view is off, the correction is NOT automatically applied in acr, however, if one selects geometry and applies guides, the metadata for the correction which is embedded in the dng is then applied. This gives tons of flexibility actually. Overall the corrections are well done in the camera. All the above of course depends on assuring the perspective correction is turned on in the camera menu.
Dan - You are correct on this one. Sorry I wasn't clear about this in the text.
I love this feature on my M10-R, and would really like to see this make its way to the Q2.
... and the M10-P, and the original Q, and so on, and so on.
I agree.
Hi Allen
Thanks for your great article!
Too few people after 1849-1990 care or know about perspective correction. We need a thorough list of PC capable cameras.
Let’s start with what I know because I’ve used it. Similar features I.e. digital PC are built in to other cameras. My Nikon D800 corrects perspective in jpgs after the shot in retouch.
So does my iPhone 11 Pro. So does the 4/3 Olympus F, although this Leica method is the nicest yet!
I have of course used perspective control lenses and way back in my studio days a 4x5 view camera. For traveling/stock however, the IN CAMERA method saves weight and TSA trouble. As pointed out, photoshop CS4-on does it too, but then it’s too late to go back and reshoot.
BTW: I love the feature with the 14 & 17-35 f2.8 Nikkors. I have a 17-35 ‘system in one lens’ review and World Trade customer shot on the 17-35/2.8. Somehow I’m called”null”. I’m Jeff. Please name me. Thanks!
Hi Jeff,
Let's not forget the Hasselblad ArcBody - a film camera that can be easily adapted with a digital back. If memory serves me right the Nikon D5000 also had a post-capture PC-Control feature that I used while reviewing the camera. It's extremely handy to have but like you mentioned - the real-time aspect of Leica's system is what makes it so attractive.
Keep them lines straight!
-AW