Back in pre-digital days, the only way to correct perspective in architectural pictures was with a tilt-shift lens. Using such a lens remedies the “keystoning” effect you get when pointing a lens upwards at a building, where all verticals in the picture converge.
A Nikon 19mm f/4 PC-E tilt-shift lens. Photo: Jeffrey M Dean at English Wikipedia [CC BY-SA]
Tilt-shift lens vs digital perspective correction
Two benefits spring to mind when comparing a tilt-shift lens to digital perspective correction:
- Image quality suffers when you digitally alter perspective in editing software. The degree to which this is noticeable varies and is likely to be trivial for most purposes. But, you’ll often notice mild degradation at 100%.
- Most digital perspective tools crop the image, effectively reducing the resolution of the image sensor. And because the image is cropped, you lose WYSIWYG (what you see is what you get) predictability when taking photos.
These factors are serious if you’re a pro photographer creating architectural photos for commercial clients. A tilt-shift lens maintains image quality and full resolution. You’d normally use a tripod with such a lens.
Using Adobe software to correct perspective
Correcting perspective has been possible in Photoshop for a long time, but it became easier from CS2 onwards. That edition introduced the Lens Correction tool.
Fixing perspective using the Lens Correction tool of 13-year-old Adobe Photoshop CS3.
In 2013, Adobe introduced automatic perspective correction, which saved considerable time compared to manual adjustments. Even today, many of Adobe’s competitors do not offer this luxury. You can fix the perspective in ACR or Lightroom within seconds.
If this feature is important to you but you don’t necessarily want to sign up for Adobe software, what else is out there?
Correct Perspective in Other Software
The idea for this article came about when I decided to break away from my Adobe subscription. I take a lot of building photos, so perspective-correction tools are useful to me. Programs vary a lot in what they offer in this regard. (In fact, a lot of the stuff you take for granted with Adobe goes AWOL if you go-a-wandering.)
DxO Viewpoint
I was using DxO Viewpoint a decade or more ago. It’s been around a while. At that time, it seemed quicker to use than Photoshop for perspective correction. Then, as now, ViewPoint worked as either a plugin or a standalone app.
I shot this from below, so there was keystoning in the original image. The auto controls in ViewPoint 3 have fixed it, making it look like I shot the Art Nouveau sign from directly in front.
DxO Viewpoint also blends seamlessly into DxO PhotoLab as a module. It’s a little controversial that DxO makes you pay extra for perspective correction, but maybe that modular system helps keep the entry price down.
A short time ago, I upgraded from ViewPoint 1 to ViewPoint 3. The latter offers automatic corrections, so I no longer have to place anchor points on each image. Sometimes it’s necessary to correct perspective manually, but the auto function saves a lot of time.
Paintshop Pro 2020
Paintshop Pro has a good perspective tool that is akin to perspective cropping in Photoshop. While it’s not a one-click solution, it’s still quick and easy to use. A grid inside the crop area lets you check all the lines as you work. This is like using ViewPoint manually, where you force parallelism by setting the position of vertical and/or horizontal lines.
If you’re only fixing verticals with the Paintshop Pro perspective tool, you must keep the horizontal lines in the grid level (or vice-versa).
By checking the “crop image” box before applying your adjustment, Paintshop Pro will automatically crop the image to its largest usable dimensions. One thing you can’t do is adjust the intensity of the effect after applying it. You’d have to go back and redo it if you weren’t happy with the result.
ACDSee Photo Studio Ultimate 2020
I’m fond of ACDSee Photo Studio Ultimate for its comprehensive dual-set of editing tools and its DAM capabilities. But how is it for perspective control? Like many photo editors, the tools are all manual whether you’re in Develop or Edit mode.
If you’re only looking to correct verticals, you can achieve that easily with the vertical slider in Develop mode. This mode is really meant for raw files, but you can run rendered files through it just like you can with ACR.
An adjustment of the vertical slider in ACDSee’s Develop mode has fixed some mild keystoning here.
In ACDSee’s Edit mode, you get perspective cropping like that of Photoshop, but it differs in one notable way. As you drag the corner points, the perspective changes in real-time, so you get to preview the result before saving it. A downside is the lack of auto-cropping. That means you need to crop separately if you drag points inside of the image frame.
Hugin
The main purpose of Hugin is to stitch photos together for panoramas, but it also corrects perspective. And, it’s free!
There are downsides.
You have to go through the motions of creating project files, the software doesn’t preserve aspect ratio, and it strips out EXIF data. You also lose a chunk of the image to cropping, but that’s normal. Hugin will give you the largest usable area after the correction.
I fix verticals in Hugin by creating a fake one-image panoramic.
If you’re familiar with Hugin and know ways around the problems mentioned above, please let me know. Since auto perspective correction is absent from many high-end photo editors, this program is worth knowing about. Although its chief role is creating panoramic photos, perspective correction is an inherent part of that process. Hugin is good at it.
Below is a quick summary of the Hugin process (or the one I use) to correct verticals:
- Open the panorama editor, then open the simple interface
- Click on “Load Images” and load the file you want to correct
- Agree to add image to current project if a dialogue box pops up
- Click on “Align”
- Click on “Create panorama” even though you’re not creating one
- Set output parameters
- Save project
- Hugin says it is stitching – it isn’t, but it is processing the file. You’ll see “batch successfully completed” in another window.
That’s it. Your corrected image awaits.
You can also perform vertical and horizontal perspective corrections as per this article. I tend not to make drastic corrections because they have a negative effect on image quality. If you shift the subject a lot, a large part of the image will look soft.
A final Hugin corrected image with original in the inset.
Darktable
Darktable is a raw processor of amazing depth. Its learning curve is steep, but it deserves a place in this article for its perspective correction module. You can correct perspective with one click, which is rare in free editing software. It might be unique. As well, there’s automatic cropping with “original aspect ratio” or “largest area” options.
A “get structure” button color codes lines in the image and tells you what the software has concluded about them. For example, a green line is a relevant vertical converging line, while a red line is vertical but not included as one of the converging verticals. You can adjust the status of these lines if you think the software has made a bad call.
This is what appears if you hit “get structure” in Darktable. You can see the software is pretty good at telling true verticals (green) from false angled or curving verticals (red).
The only thing you can’t do in Darktable is back off the auto adjustment if you want a slightly converging result. You’d have to edit manually for that. But still, this feature is superb.
Honorable mentions
Naturally, other photo editors also include perspective correction. Capture One is one of the most evolved pieces of photo software I’ve seen. Its perspective control is like that of ViewPoint in manual mode, where you line up verticals or horizontals by hand to correct the image.
Programs like ON1 Photo Raw, Luminar and Exposure allow perspective control via a familiar system of sliders. You align the architectural lines of a photo with the lines of a grid. It works, but there’s no auto mode.
Am I obsessed with auto mode? Kind of, because it’s fast and does a good job. If you can tweak the result, so much the better.
The clean interface and “Canvas” toolset of Luminar 4, including perspective sliders.
Bottom Line
If you’re straying from Adobe and need perspective correction, I’ve gotta give top prize to DxO ViewPoint 3.
You can manually adjust perspective to your heart’s content or have the software swiftly do it for you. Importantly, you can back up a bit from auto results if the verticals look too forced.
The standalone ViewPoint 3 also includes an attractive browser, corrects for volume deformation and offers a tilt-shift “miniature effect”. What’s not to like?
The ViewPoint 3 browser.
For those that don’t want to pay extra for this functionality, look at Darktable. You might be scratching your head at its vast array of modules, but persistence pays off. Its perspective control is great at this price point!
All the software mentioned is eminently usable, so it’s a question of how valuable one-click corrections and versatility are to you. I hope I’ve helped in a few decisions.
Do you know any other software that helps correct perspective in photography? Share with us in the comments!
