Get things in perspective using Photoshop CS5
Learn the techniques needed to fix warped lines and skewed perspectives in Adobe Photoshop CS5. Click here to Watch & Learn
There are two sorts of distortion that are seen regularly in photography – geometric and perspective. The former type is caused by limitations of the lens and makes straight lines appear bendy. The way the lines curve defines the form of geometric distortion going on.
With pin-cushion distortion, they bow in towards the centre of the image – think of pressing your finger into the middle of a chequered cushion. Conversely, barrel distortion makes lines bow outwards, as though the pillow is overly stuffed.
Both types of geometric distortion occur with fixed focal length lenses, but they are more common with zoom lenses, especially those with very wide focal ranges. Pin-cushion distortion is most common with telephoto lenses, and barrel with wide-angle optics.
Perspective distortion is the converging vertical phenomenon that makes buildings look smaller at the top than the bottom. It’s often associated with wide-angle lenses, but if a subject is shot from the same distance with a short focal length lens and a telephoto optic, the two images will show the same degree of perspective distortion.
However, short focal length lenses have a wider angle of view, so are often used closer to the subject to avoid an empty foreground. Consequently, the subject looks larger relative to the background, perspective is exaggerated and tall buildings shot from low down look huge. Fortunately, both geometric and perspective distortion can be corrected using Photoshop.
This entry was posted on Friday, July 22nd, 2011 at 2:29 pm and is filed under Tutorials. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a comment. Pinging is currently not allowed.