Message 21 Juin 2011, 23:01

Correct the defects of wide-angle lenses with Photoshop

With a wide angle lens, there are two types of distortion: barrel distortion and pincushion distortion.
Depending on the focus distance and focal length used, distortion varies.
On the longer distances, there will be a barrel distortion, while the lines are convex distorted outwards.
In this case the buildings seem inflated, the horizon is distorted and forms a kind of bubble.
The shortest distances, there will be a pincushion, while the lines are concave, bent inwards.
If the higher of the focal length used is small (10 mm - 20 mm) more than the deformation is important.
The use of this property is interesting for the aesthetic and artistic photos for example using "Fish eyes" lens, but in most cases (landscape photos), it is not the desired effect and it affects the photo.

There is a tool built into Photoshop, easy to use and can correct many flaws:
- The barrel and pincushion distortion
- The outlook and inclination
- The chromatic aberrations
- The vignetting (when using wide angle filter for example)

I propose to enhance this tutorial two images, one with pincushion distortion and the other barrel.

This first photo was a pincushion distortion of the lens, it was cropped very close, and taken at a distance
relatively short.

Photo01.jpg
Photo01.jpg (264.02 Kio) Consulté 4980 fois


To correct this distortion, click in the menu of Photoshop on "Filter" / "Distort" / "Lens Correction"

Photo02.JPG
Photo02.JPG (126.89 Kio) Consulté 4980 fois


The photo appears in a new window, a grid is automatically added in order to correct deformities
accurately. On the right, the menu that allows you to apply a lot of corrections.
Here is the corrected photo, just simply move one slider, to remove the distortion.

Photo03.JPG
Photo03.JPG (198.88 Kio) Consulté 4980 fois


By varying the cursor indicated by a red arrow to the left, we correct the pincushion distortion.

Photo04.JPG
Photo04.JPG (114.38 Kio) Consulté 4980 fois




Here is another picture with a barrel distortion, the horizon is not straight but curved.
When we took pictures of landscapes, one is often faced with this deformation.

Photo05.jpg
Photo05.jpg (266.94 Kio) Consulté 4980 fois


Simply move the cursor to the right this time around to correct the deformity.
As can be seen, this correction introduces voids in the top, bottom, left and right.
This will require, for this type of photo, to be careful to frame a little wider in order to crop the photo.

Photo06.JPG
Photo06.JPG (180.98 Kio) Consulté 4980 fois


To crop a photo, use the tool designated by a red arrow.
For clarification on how to crop a photo tutorial please refer to "straighten a photo in Photoshop"
present on this forum in the "Photoshop Tutorials".

Photo07.JPG
Photo07.JPG (212.94 Kio) Consulté 4980 fois


This is the final result, there is no deformation of the horizon, the picture is cropped.

Photo08.jpg
Photo08.jpg (266.27 Kio) Consulté 4980 fois
NIKON D7100 *** NIKON 17-55 mm AF-S DX f/2.8G G IF ED *** SIGMA 70-200 mm F2,8 APO DG OS EX HSM Nikon D *** SIGMA 120-400mm F4,5-5,6 DG APO OS HSM Nikon D *** SIGMA 105mm F2.8 EX DG MACRO OS HSM *** SIGMA 8-16 mm F4.5-5.6 DC HSM *** Flash SB600