Review: SKRWT helps fixing perspective distortions

SKRWT app survived many spring cleanings on my iPhone. It's an excellent app that does one job and does it extremely well: It helps you to fix perspective distortions of your architecture photos and makes them look way better. It's one of the few iPhone apps I use it regularly.

If you can't wait, here's the iTunes App Store Link where you can download SKRWT.

SKRWT works no matter if you took a photo with the iPhone, a GoPro or even a DSLR. The developers did an excellent job and recently updated the app improving the overall workflow.

What I love is that SKRWT leaves the resolution of your photo intact. Many other tool I've tried will reduce the resolution of your photos. Here's a before and after comparison of a photo I've edited with SKRWT.

Before and after comparison of photo resolution of a photo I edited with SKRWT

Since I use SKRWT I've had a few cases were SKRWT reduced the file size by 5 to 10 pixels. That's nothing compared to other tools which reduce the resolution by 100s of pixels.

 

This is how crooked or bent lines look like and how to fix them with SKRWT

Perspective distortions like crooked lines occur no matter what kind of camera you use unless you use a special lens with your DSLR; such lenses costs start at around $900, that is. 

Look at the photo below that I took In Bucharest, Romania. The building is the CEC Palace and it's the headquarter of the national savings bank. To illustrate the crooked lines in the photo, I've added two red lines.

Crooked lines in a photo of the CEC Palace in Bucharest, Romania. 

Crooked lines in a photo of the CEC Palace in Bucharest, Romania. 

You'll get crooked lines when you photograph a large building from the street level. The closer you are to the building, and the more you have to tilt your camera upwards to get the whole building, the stronger is the crooked lines effect will be. 

Because of the crooked lines the building looks like it tips over backwards. Crooked lines are an example for vertical perspective distortion. 

Ideally the edges of the building would be parallel to the borders of your photo. And this is where SKRWT comes in. You can easily fix that with SKRWT and afterwards the above photo looks like this:

Crooked lines fixed in a photo of the CEC Palace Bucharest, Romania

Crooked lines fixed in a photo of the CEC Palace Bucharest, Romania

Then there is horizontal perspective distortions. That occurs if you don't stand perfectly in front of the building you photograph. But sometimes it's just not possible to do that.

Here's a shot from a sturdy remains from world war II that still exists in Vienna. The red lines illustrate the horizontal perspective distortion. They should be even.

vertical-perspective-distortion-example.jpg

SKRWT can fix that, too. Here's the final shot with the perspective distortion fixed (and some other adjustments) right on the iPhone:

vertical-perspective-distortion-fixed.jpg

The next shot I took Prague shows how to fix the bent lines distortion. Bent lines typically occur when using a wide angle lens or shooting a panorama. The photo is a vertical panorama of one the towers at the famous Charles Bridge.

Because I was close to the tower and took a vertical panorama shot, the lines (edges) of the tower are bent. The edges of the tower should ideally be aligned with the red lines. Instead, they're bent towards the top of the photo.

Bent lines; Tower at the Charles Bridge in Prague, Czech Republic

Bent lines; Tower at the Charles Bridge in Prague, Czech Republic

You've guessed it :) SKRWT offers a way to fix that, too. Here's the photo after I processed it using the wide angle perspective distortion fix. The bent lines are gone and the edges are perfectly straight and it took me less than 3 seconds to fix that.

Bent lines fixed; Tower at the Charles Bridge in Prague, Czech Republic

Bent lines fixed; Tower at the Charles Bridge in Prague, Czech Republic

How to fix perspective distortions with SKRT

Now let me show you how to fix different perspective and lens distortions with SKRWT.

Launch SKRWT on your iPhone/iPad and you'll see a splash screen with two options. Either you take a photo with the app by tapping the (left) camera symbol or you open a photo already on your device by tapping the (right) camera roll symbol.

I use a dedicated camera apps to shoot, so I only used the app with photos from my camera roll so far.

SKRWT start screen

SKRWT start screen

Tap the right symbol to open a photo picker to select a photo from the camera roll. SKRWT displays almost all your albums, even the favorites (Not all apps display this album for whatever reason). Another reason to love SKRWT!

I usually pick a photo from the "recently added" album. This album displays the most recent shots in descending order.

Did you notice the small sort button at the bottom of the screen? Tap this button to enter the photo picker configuration mode. Now you can rearrange the albums in the photo picker by tapping, holding and dragging them. Hide albums you don't want to use by tapping on the eye symbol. "White eyed" albums are displayed, others are not.

For example, I've hidden all my shared iPhone photo streams. 

SKRWT image picker configuration

SKRWT image picker configuration

To make your adjustments permanent tap "confirm" on the lower right corner.

Now select an album and chose a photo you want to work with. The photo will be loaded as a preview.

Swipe left and right to load the previous (or next) image from the album into the preview or tap the photo in the preview and see the EXIF metadata. Awesome! Now tap "import" in the lower right corner to load the photo from the preview into the editor.

All the editing functions are located in the toolbar at the bottom of the screen. In the recent update, the developers moved all controls to the bottom of the screen which is awesome if you're using a bigger device like the iPhone 6+! Photo app developers, take note! This makes working with an app much easier on an iPhone 6+.

SKRWT Editor

SKRWT Editor

Swipe left or right on the toolbar at the bottom to access all the editing functions in SKRWT. After you've loaded the photo into the editor, you'll see the 6 icons above. From left to right, the buttons do the following:

  • Undo last step
  • Straighten photo 
  • Fix horizontal distortion
  • Fix vertical distortion
  • Fix wide angle distortion
  • Fix Ratio

Let's start and fix the vertical distortion (crooked lines) you'll get when photographing a building from the street level. I'll use the example photo from above.

Tap the 4th icon from the left. A grid helping you align the lines will be displayed and the bottom toolbar changes to scrollable dial.

skrwt-review-step-by-step-4.jpg

Now swipe the dial to the left or right. If you need to fix the usual crooked lines from photographing a building from the street level, swipe the dial to the left until the e.g. the edges of the bibuilding are perfectly aligned with the grid.

Pro Tip! When you photograph a building include some empty space (1/4 to 1/3 of the entire frame) above the building in your photo so you can work with SKRWT! Otherwise your building will be moved out of the frame and cropped like in this shot of the CEC Palace.

Building get's cropped at the top

Building get's cropped at the top

Once you're done and satisfied with the results, tap the checkmark icon at the bottom of the screen. You can choose between different options how you want to save (or share) the photos

skrwt-review-step-by-step-7.jpg
  • "Share to Instagram" is pretty obvious, right?
  • "Save to camera roll" will save the photo to your camera roll leaving the original photo untouched.
  • "Open in MRRW" opens the photo in a special editor for applying all kinds of mirroring effects (requires in-app purchase)
  • "Replace" will save your edited photo over the original photos! 
  • "Open In" will open the photo in another app to continue editing

An that's it! pretty simple, right? It works the same for all kinds of perspective and lens distortion fixes. You can even apply several fixes one after another, like first fixing the lens distortion, then fixing perspective distortions.

Conclusion: You should really look at SKRWT if you frequently photograph e.g. buildings or create lots of panoramas. The app really is worth the money and helps you to improve your photos. As I mentioned at the beginning: The app survived many app spring cleanings  and I use it regularly. For  good reason!