What is lens distortion and what to do about it | Articles | Photo, video, optics

Pho­tog­ra­phers from time to time encounter geo­met­ric dis­tor­tions in their images. As a result, the pic­ture in the pho­to looks almost like in real­i­ty, but there are some defects. For exam­ple, the build­ing is not even, but taper­ing upwards. One pop­u­lar type of dis­tor­tion is dis­tor­tion. About what dis­tor­tion is, about its types and how to fix or avoid it, they told in this arti­cle.

One pop­u­lar exam­ple of dis­tor­tion is the fish­eye effect. Pho­to: wallhere.com

What is dis­tor­tion
Types of lens dis­tor­tion
How to use dis­tor­tion for cre­ative shots
How to pre­vent cur­va­ture
How to fix lens dis­tor­tion in pho­to edi­tor
Ortho­scop­ic lens­es
Nikon AF NIKKOR 20mm f/2.8D
Canon EF 14mm f/2.8L II USM
Canon TS‑E 17mm f/4L Tilt-Shift
Laowa 9mm f/5.6FF RL
Voigt­lander Nok­ton 10.5mm f/0.95 MFT
Sony FE 12–24mm f/4G (SEL1224G)
Samyang XP 10mm F3.5

What is distortion

Dis­tor­tion is the dis­tor­tion of an image. In the pho­to, all lines should be even (hor­i­zon­tal and ver­ti­cal). But some­times in the pic­tures you can see that the objects are slight­ly (or strong­ly) curved.

The most com­mon­ly affect­ed lens­es are:

- super­zooms (for exam­ple: Nikon 18–200 mm, Canon EF‑S 18–135 mm). When you change the focal length, the geom­e­try of the pic­ture changes. Either a “bar­rel” or a “cush­ion” appears (we will talk about what it is in the block about the types of dis­tor­tion);

- wide angle (Canon 15–85 mm, Nikon 16–85 mm). At the min­i­mum focal length, a strong “bar­rel”. To fix the prob­lem, you need to add zoom;

- very rarely tele­pho­to lens­es (70–300 mm). At the max­i­mum focal length there is a “cush­ion”.

Most often, dis­tor­tion occurs with wide-angle lens­es. Max­i­mum dis­tor­tion occurs at min­i­mum focal length and wide view­ing angle.

What caus­es dis­tor­tion in a pho­to? The rea­son is the fea­tures of the opti­cal sys­tem of the cam­era. Rays of light that pass through a lens focus dif­fer­ent­ly on it. The cen­tral ones run in one direc­tion, the extreme ones in the oth­er. A devi­a­tion from the real geom­e­try is formed. Cur­va­ture often appears when using cheap equip­ment or shoot­ing tall build­ings from a low point.

Impor­tant: Per­spec­tive dis­tor­tion is not entire­ly cor­rect to attribute to dis­tor­tion. It is solved with the help of a Tilt-shift lens. This was dis­cussed in detail in the blog.

Types of lens distortion

Types of dis­tor­tion. Pho­to: studfile.net

Dis­tor­tion hap­pens:

• pos­i­tive (“pil­low”) — the frame is com­pressed, the image seems to be clamped in the cen­ter;
• neg­a­tive (“bar­rel”) — the image is stretched, the dis­tance from the opti­cal cen­ter increas­es.

An exag­ger­at­ed exam­ple of a “bar­rel”. Pho­to: www.stackoverflow.com

How to use distortion for creative shots

Some­one strives to get rid of any dis­tor­tion as much as pos­si­ble and take pic­tures with per­fect geom­e­try. And some­one, on the con­trary, uses any oppor­tu­ni­ty to cre­ate unusu­al cre­ative shots. That is why lens dis­tor­tion has so many fans. For lovers of espe­cial­ly notice­able dis­tor­tions, there is even a spe­cial fish­eye lens. A selec­tion of the best col­lect­ed in the blog.

This is ultra-wide-angle equip­ment that delib­er­ate­ly uses dis­tor­tion. With the help of such equip­ment, you can take “bar­rel-shaped pic­tures”.

For exam­ple, this way you can unusu­al­ly pho­to­graph build­ings. Pho­to: photosition.blogspot.com

How to prevent curvature

You can do this in 3 ways:

• shoot from a mid­point rather than a low one, use lens­es with a fixed focal length or good zoom devices;
• fix cur­va­ture in edi­tor;
• buy an ortho­scop­ic lens (in which there is no dis­tor­tion or it is insignif­i­cant).

How to fix lens distortion in photo editor

In most cas­es, the cur­va­ture can be cor­rect­ed in graph­ic edi­tors. The pic­ture will even­tu­al­ly become more pro­por­tion­al, famil­iar to the human eye.

But it is impor­tant to under­stand that part of the frame (edges) will have to be cut off. There­fore, it is bet­ter to take pic­tures imme­di­ate­ly with a mar­gin, leav­ing space around the edges.

To auto­mat­i­cal­ly cor­rect dis­tor­tion in Pho­to­shop, you need:

- open a snap­shot;

- select tab “Fil­ter” / “Fil­ter”;

- click on the line “Dis­tor­tion Cor­rec­tion” / “Lens Cor­rec­tion”;

- a new win­dow will open. Select on the right “Auto Cor­rec­tion” / “Auto Cor­rec­tion”;

- define the para­me­ters: “Cor­rec­tion” / “Cor­rec­tion”, “Search Cri­te­ria” / “Search Cri­te­ria”, “Lens Profiles”/“Lens Pro­files”.

Set up auto­mat­ic fix. Pho­to: polovinkiina99.blogspot.com

one. “Cor­rec­tion” - you need to select the prob­lems that need to be fixed. In the “Edge” menu, you can choose what hap­pens to the emp­ty areas that appear after the cor­rec­tion. They can be made trans­par­ent, col­ored, or the out­er pix­els of the pic­ture can be stretched onto them.

2. “Search Cri­te­ria” — you need to select the brand, mod­el of the cam­era and lens. This helps in more accu­rate cor­rec­tion;

3. “Lens Pro­files” - choose the appro­pri­ate one.

Man­u­al fix:

– open image;

- select tab “Fil­ter” / “Fil­ter”;

- click on the line “Dis­tor­tion Cor­rec­tion” / “Lens Cor­rec­tion”;

- a new win­dow will open. Select on the right “Manual”/“Custom”;

- then you need to drag the slid­er under the inscrip­tion “Dis­tor­tion” / “Geo­met­ric Dis­tor­tion” left or right to achieve the desired effect.

Any changes must be saved for them to take effect.

Man­u­al fix. Pho­to: polovinkiina99.blogspot.com

Orthoscopic lenses

This type of equip­ment is lens­es that are free from dis­tor­tion. Or in them it is very small and prac­ti­cal­ly does not affect the image.

Now let’s talk about wide-angle lens­es with min­i­mal dis­tor­tion (since this type of optics usu­al­ly caus­es a prob­lem).

Nikon AF NIKKOR 20mm f/2.8D

One of Nikon’s most pop­u­lar lens­es. This line has been pop­u­lar for over 20 years. Light­weight (270 g) and com­pact, there is dis­tor­tion cor­rec­tion at close dis­tances. Suit­able for trav­el, city shoot­ing. A uni­ver­sal assis­tant with which the lines will always remain straight.

Canon EF 14mm f/2.8L II USM

An ultra wide-angle lens is indis­pens­able for shoot­ing land­scapes, archi­tec­ture and inte­ri­ors. The mod­el is includ­ed in the pro­fes­sion­al L‑series, which guar­an­tees high qual­i­ty and reli­a­bil­i­ty. Of the advan­tages: low dis­tor­tion, hous­ing pro­tect­ed from dust and mois­ture, the abil­i­ty to man­u­al­ly cor­rect the focus at any time.

Canon TS‑E 17mm f/4L Tilt-Shift

A unique mod­el that was released in 2009, but remains in demand. The tilt-shift design allows you to shift the lens­es installed in the device rel­a­tive to the cam­era matrix. Thanks to this, you can get rid of the dis­tor­tion that occurs when shoot­ing with a con­ven­tion­al lens, and work with per­spec­tive. The device is char­ac­ter­ized by high sharp­ness and min­i­mal dis­tor­tion.

What the unusu­al Canon TS‑E 17mm f/4L Tilt-Shift looks like. Pho­to: 999.md

Laowa 9mm f/5.6FF RL

Wide-angle ortho­scop­ic lens for full-frame mir­ror­less cam­eras. It is active­ly used for shoot­ing archi­tec­ture and land­scapes. There are mounts for Leica M, L, Sony E and Nikon Z.

Voigtlander Nokton 10.5mm f/0.95 MFT

This is not a fish­eye, as it might seem at first glance. And ortho­scop­ic, with “cor­rect­ed geom­e­try” (despite the small focal length). There are prac­ti­cal­ly no lin­ear dis­tor­tions, and the view­ing angle is 93 degrees. High sharp­ness even at wide aper­tures.

Sam­ple shots tak­en with the Voigt­lander Nok­ton 10.5mm f/0.95 MFT lens. Pho­to: mirrorlessons.com

Sony FE 12–24mm f/4G (SEL1224G)

Ultra wide-angle that cap­tures a wide view­ing angle. This is espe­cial­ly impor­tant when shoot­ing land­scapes. The image is sharp and con­trasty through­out the image. Aut­o­fo­cus is fast and qui­et.

Samyang XP 10mm F3.5

Full frame lens from a South Kore­an man­u­fac­tur­er. It pro­vides a view­ing angle of 139 degrees. Suit­able for shoot­ing archi­tec­tur­al objects and land­scapes. There is a mount for Canon EF and Nikon F.

We hope that our mate­r­i­al helped you under­stand what lens dis­tor­tion is, how to avoid it and fix it.