Photo distortion can leave you disappointed with your photography and blame your Android or iPhone camera. Typical distortion attributes to a recognisable smartphone photo... especially indoors and architecture photos.

Indoor photos that contain vertical and horizontal lines can be problematic. A cheap lens attachment can make these lines bend and warp. This is not as noticeable in the outdoors where there are fewer straight lines. The good news is you can minimise this with an understanding of what causes distortion.

There is a lot of misinformation out there believed by many that perspective and lens distortion as the same.

If you prefer to learn by watching or listening instead of reading, I have included YouTube and Podcast links above.

We are going to cover some different distortion issues that have experienced in your photography:

Lens - barrel and pincushion distortion

Perspective - lens to subject distance and angle perspective distortion

This distortion is common in a wide-angle lens. The lens built-in into your smartphone is a wide-angle lens. The barrel distortion in the default camera is not very noticeable due to algorithms and image processing. The distortion becomes quite noticeable in most circumstances when you add a wide-angle lens attachment to the phone.

Your smartphone is designed to gather and process the information from the field of view of the standard built-in lens. When we attach a wide-angle lens to the phone, it needs to squeeze that extra context onto the same image sensor.

Straight lines in the scene will bend outwards and is most noticeable along the edges of the photo. Lens distortion is less noticeable in the centre as less light bends to reach the sensor in the middle.

Most fisheye lenses are so extreme that the shape of the image is circular rather than the normal rectangular shape.

Opposite to barrel, straight lines curve inward from the edges looking squashed in the middle of the photo! This distortion is more found in zoom lenses. Zoom lenses increase magnification from the centre to the edges.

SKRWT is one of my favourite single-purpose photo editing apps available in both the Google Play Store and Apple App Store. It is not an all-in-one photo editing app. Correcting and introducing different types of distortion is all it does and it does it well.

It is less than the price of a coffee. Even I would trade a coffee for this app because it's amazing! Removal of both barrel and pincushion distortion is as simple as swiping on a slider.

Have you seen those creative photos of someone appearing to hold a large known object in their hand? This is achieved by the large object being well in the distance and the camera angled to make it look like it is in their hand. Objects further away appear smaller. This is even more so when you have a wide-angle lens on your smartphone camera. You have likely seen a beautiful sunset and raised your phone in excitement to be disappointed that the sunset is tiny on your screen!

Another example of distance to camera distortion is portrait photos. Have you noticed that if you hold the phone close to a persons face, their ears look smaller and appear to move around behind their head? Their nose also looks unflattering larger. This is another example of closer objects to the lens appear larger.

Most photographers believe distorted facial features is the result of the wide-angel lens. The truth is that it is all about your distance from the subject. If you tap on the telephone 2X lens option on your smartphone you need to step back to fit the whole face in the frame. It is this distance back from the subject that is making everything appear more naturally.

As objects become further away, they appear smaller. You have seen those roads or train track photos highlighting the converging lines. This is even more emphasized when you shoot from a lower angle! Another example is standing at the bottom of a building. The ground level is closer to you is super wide. As you look up, the top floors further away from our vantage point begin to narrow. Be careful you don't fall over if you do this!

Buildings captured at ground level using a smartphone with a built-in wide-angle lens further emphasises this converging vertical. If you want to get creative, you can stand close and angle the smartphone to shoot upward toward the top of the building. This dramatic emphasis of the building narrowing is known as 'keystoning.'

My favourite apps for correcting perspective distortion is Snapseed.
Inside the app, go to Tools then Perspective. At the bottom of the screen, you have three icons. The Perspective icon reveals and hides the four tools available: Tilt, Rotate, Scale and Free. As you tap each of these options, an icon appears in the middle of your photo to confirm the mode you selected. How cool are they? Now, tap on Tilt again to reveal the two arrow icons in the middle of your photo.

The second icon at the bottom is the Fill mode that will become clearer when we start playing with this tool. The three options here are Smart, White and Black. Tap on Smart. The third icon at the bottom is Autocorrect. Don't bother with that one!

Next, place your finger on the photo preview and swipe up and down. The grid overlay now has more lines to help you align elements in the photo with a straight line. This is very helpful for straight poles of edges of buildings! The photo stretches to make either the top or bottom of the photo narrow. This counteracts the tapering that occurred at the original capture. The third thing that happens here is even cooler, it magically creates and fills in areas that are not there! It is a process called 'content-aware fill.' It looks at the existing content inside the edges of the frame and fills in the missing bits. So cool!! Don't forget to tap on the tick to confirm you want to apply this adjustment.

Now, swipe left and right to see how you can either correct angle perspective on a horizontal axis. I normally use this for a creative effect than a corrective technique.

Another very effective app for fixing perspective is Adobe Lightroom mobile. One of the few additional tools available on a subscription plan is the Geometry tool. The guided tool allows you to place reference vertical and horizontal lines in your photo. The software will then warp the photo to change the vertical and horizontal perspectives.