Message 01 Avr 2011, 23:33

Correct the perspective with Photoshop

This tutorial will help you correct the perspective of your photos with Photoshop.
One of the main problems when doing architectural photographs,
what are the prospects.
These distortions are mainly due to the lens, but also to the view selected
during the shooting. The ideal is to be halfway up the building, facing it and
by choosing a focal length greater than 50 mm.
In practice this is often not the case.
To correct the problems and vertical proportions of the buildings, we have several
possibilities with Photoshop.

NB: If you have problems to viewing images in this tutorial:
Right click on the white square with a red and click on the image display.

The photo below is a very good example photo with problems of perspective (Photo
taken with a focal length of 18 mm, a tower at left, and shooting point is located
very close to the ground).

Photo01.jpg
Photo01.jpg (479.09 Kio) Consulté 5937 fois


For convenience, you can use the grid in Photoshop (which I have not done for this tutorial).
To display the grid, click the menu "View / Show / grid ", or use the key combination CTRL + '
To stop displaying the grid back into the menu to click on the "grid" or combination of CTRL + '

In Photoshop, load your image, click on the "Move tool" (1),
then on the menu "Select" / "all" (2), as below.

Photo02.JPG
Photo02.JPG (89.3 Kio) Consulté 5937 fois


The whole image is selected, click on one corner of the selection
with the mouse by left click (1),
the selection should change, from dotted lines, to solid lines.
Position your mouse over the image and right click with the mouse,
the transformation menu appears (2), as below

Photo03.JPG
Photo03.JPG (142.28 Kio) Consulté 5937 fois


First possibility:
Use the option menu "Perspective", then click the left mouse button and
keep the button on one of the 4 corners. Drag your mouse from left to right,
from right to left, the two sides of the selection moves at the same time, as below.

Photo04.JPG
Photo04.JPG (191.92 Kio) Consulté 5937 fois


This technique is well, if you're really in front of the building and the heights of
building on the left and right are the same.
In our case, on the photo above, a red arrow shows a horizontal defect
on the top of the tower and, the middle and the right side of the building, retains the problems of perspective.

Second possibility:
Use the "Skew" option on the menu, then click with the left mouse button and
keep the button on one of the 4 corners. Drag your mouse from left to right, for example,
only the angle of your chose distorts the picture.
As you can see in the picture below, by adjusting the corner at the top left and bottom right corner,
prospects are relatively well adjusted

Photo05.JPG
Photo05.JPG (201.76 Kio) Consulté 5937 fois


Below the photo cropped (with the "Crop tool").
The tower is right, its top is horizontal. The vertical middle of the building are now correct
those of the right side of the building are not fully recovered to preserve the realism associated with the
shooting point,who is not quite in the middle of the building

Photo06.jpg
Photo06.jpg (463.01 Kio) Consulté 5937 fois


You now know two techniques that allow you to fix almost all faults
perspective of your photos, Do not overtighten your photos when shooting because, as you may have noticed,
to correct perspective also leads a crop of your image with the crop tool.




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Visit the full site (tips and tricks on photography, such as broadcasters, lightning detection, ...): http://rienquepourlesyeux.free.fr

And if you have any comments, suggestions and / or information on this tutorial, feel free to reply to this post.
You can also post your own tutorials, photos, the forum is open to all those who love photography.
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