<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html
  PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!--#config errmsg="" --><!-- saved from url=(0022)http://help.adobe.com/ -->
<html lang="en-us">
    <head>
        <meta http-equiv="content-type" content="text/html; charset=UTF-8" />
        <meta name="lang" content="en-us" />
        <meta name="area" content="livedocs" />
        <title>Adobe Photoshop CS4 * About lens distortion</title>
        <meta name="product" content="Photoshop" />
        <meta name="keywords" content="" />
        <script type="text/javascript" language="Javascript" charset="UTF-8"><!--[CDATA[
        var currentTreeNode = "WS3CFA74DE-7F17-4e26-B74E-D27137DC568Fa.html";
// ]]--></script>
<script src="terms.js" type="text/javascript" language="Javascript" charset="UTF-8">...</script> <script src="help.js" type="text/javascript" language="Javascript" charset="UTF-8">...</script>  <script src="utilities.js" type="text/javascript" language="Javascript" charset="UTF-8">...</script> <script src="event.js" type="text/javascript" language="Javascript" charset="UTF-8">...</script> <script src="treeview.js" type="text/javascript" language="Javascript" charset="UTF-8">...</script> <script src="toc.js" language="Javascript" type="text/javascript" charset="UTF-8">..</script> 
<script type="text/javascript">
<!--[CDATA[
var headId = document.getElementsByTagName("head")[0];         
if (use_ie_6_behavior) {
    var linkId = document.createElement("link");
    linkId.href = "content-ie6.css";
    linkId.rel = "stylesheet";
    linkId.type = "text/css";
    headId.appendChild(linkId);
}
function initRoboHelpDOM() {
    if (use_robohelp_behavior) {
        hideElement("searchbar");
        hideElement("hierarchy");
        hideElement("col1");
    }
}
YAHOO.util.Event.onDOMReady(initRoboHelpDOM);
// ]]-->
</script>
<!--#include virtual="/livedocs/ssi/globalheader.ssi" -->
        <link rel="stylesheet" type="text/css" href="tree.css" />
        <link rel="stylesheet" type="text/css" href="content-fonts.css" />
        <link rel="stylesheet" type="text/css" href="content-hyperlinks.css" />
        <link rel="stylesheet" type="text/css" href="content.css" />
        <link rel="stylesheet" type="text/css" href="localeSpecific.css" />
    </head>
    <body id="content_body" onload="window.focus();">
        <a name="top"></a><div id="mnemonic">
            <div class="Photoshop"><table><tr><td class="banner">Adobe Photoshop CS4</td><td class="pod"><img src="images/PDF.gif" width="16" height="16" hspace="15" valign="50%" />&#160;&#160;
                     <a title="PDF" href="http://help.adobe.com/en_US/Photoshop/11.0/photoshop_cs4_help.pdf">
                         PDF (adobe.com) 
                    </a></td></tr></table></div>
        </div>
        <div id="searchbar">
<!-- BEGIN SEARCH CONTENT -->
            <form class="search_form" id="search" name="search" action="search.html" target="_self">
                <img src="images/search.png" />
<script type="text/javascript">
<!--[CDATA[
function clearSearch(){
    if (document.search.q.value == terms_AHV_SEARCH_BUTTON){document.search.q.value = ""}; 
}
document.write('<input class=\"search_input\" \
        name=\"q\" \
        id=\"q\" \
        type=\"text\" \
        maxlength=\"256\" \
        value=\"' + terms_AHV_SEARCH_BUTTON + '\" onclick=\"clearSearch()\"><\/input>'); 
// ]]-->


</script> 
            </form>
        </div>
<!-- BEGIN PAGE CONTENT WRAPPER -->
        <div id="page_content_wrapper">
<!-- BEGIN PAGE WRAPPER -->
<table id="page_content_table">
<tr>
<td id="col1">
<!-- BEGIN IONCOMMENTCOUNT -->
            <div id="ionComCount">
            </div>
<!-- END IONCOMMENTCOUNT -->
<!-- BEGIN GROUP TOC WRAPPER -->
            
<!-- END GROUP TOC WRAPPER -->
<!-- BEGIN NAV WRAPPER -->
            <div id="group_toc">
<script type="text/javascript">
<!--[CDATA[
if ( typeof(terms_BOOK_SHORT) != 'undefined' ) {
  document.write("<p>" + terms_BOOK_SHORT + "<\/p>");
}
// ]]-->


</script> 
            </div>
            <div id="nav_content">
            </div>
<!-- END NAV WRAPPER -->
</td>
<td id="col2">
<!-- BEGIN CONTENT WRAPPER -->
<!-- BEGIN BREADCRUMBS -->
            
            <div id="breadcrumb">
                
<ul class="navigation"><li class="prev"><a accesskey="p" class="prev" href="WS3CFA74DE-7F17-4e26-B74E-D27137DC568Fa.html" title="Correcting image distortion and noise"><img src="images/blank.gif" alt="Previous" width="17" height="17" /></a></li><li class="next"><a accesskey="n" class="next" href="WSF65FB40F-00F5-445a-BD9A-38B3737A9A19a.html" title="Correct lens distortion and adjust perspective"><img src="images/blank.gif" alt="Next" width="17" height="17" /></a></li></ul><div class="hierarchy" id="hierarchy"><a href="WSfd1234e1c4b69f30ea53e41001031ab64-763ea.html">Retouching and transforming</a> /
     <a href="WS3CFA74DE-7F17-4e26-B74E-D27137DC568Fa.html"><b>Correcting image distortion and noise</b></a> 
     </div>

            </div>
<!-- END BREADCRUMBS -->
            <div id="content_wrapper">
<!-- BEGIN PAGE TITLE -->
                <h1>
                    About lens distortion
                </h1>
<!-- END PAGE TITLE -->
                <div><p><dfn class="term">Barrel
distortion</dfn> is a lens defect that causes straight lines to
bow out toward the edges of the image. <dfn class="term">Pincushion distortion</dfn> is
the opposite effect, where straight lines bend inward.</p>
<div class="fignone"><img alt="" id="tr_12" src="images/tr_12.png" /><div class="figdesc">Examples of barrel distortion (left) and pincushion distortion
(right)</div><br /></div><p><dfn class="term">Vignetting</dfn> is
a defect where the edges, especially the corners, of an image are darker
than the center. <dfn class="term">Chromatic aberration</dfn> appears as a
color fringe along the edges of objects caused by the lens focusing
on different colors of light in different planes. </p>
<p>Some lenses exhibit these defects depending on the focal length
or the f‑stop used. You can set the Lens Correction filter to use
settings based on the camera, lens, and focal length used to make
the image. </p>
</div>

                <div id="related">
                    <div class="separator">&#160;</div>
                    
                    
                </div>
                <div id="footer">
                    <p><img src="images/Community.png" />&#160;<a title="community help (adobe.com)" href="http://www.adobe.com/go/lr_Photoshop_community_en">community help (adobe.com)</a></p>
<!-- BEGIN IONCOMMENTS -->
                    <div id="ionComHere">
                    </div>
<!-- END IONCOMMENTS -->
<!--#include virtual="ionComments.ssi" -->
                    <p id="creativecommons"><a href="http://creativecommons.org/licenses/by-nc-sa/3.0/" id="creativecommons_text"><img id="creativecommons_img" src="images/CC.png" alt="This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License" /></a></p>
                </div>
            </div>
<!-- END CONTENT WRAPPER -->
</td>
</tr>
</table>
        </div>
<!-- END PAGE CONTENT WRAPPER -->
<script type="text/javascript">
<!--[CDATA[
scrollToNameAnchor();
// ]]-->
</script> 
<!--#include virtual="/livedocs/ssi/globalfooter.ssi" -->
<!--#include virtual="/ubi/analytics/analytics_ssi.html" -->
    </body>
</html>