diff --git a/components/sceneutil/lightmanager.cpp b/components/sceneutil/lightmanager.cpp
index cb6a12c879..f0fd0ef9f3 100644
--- a/components/sceneutil/lightmanager.cpp
+++ b/components/sceneutil/lightmanager.cpp
@@ -234,6 +234,7 @@ namespace SceneUtil
         {
             osg::ref_ptr<osg::StateSet> stateset = new osg::StateSet;
             std::vector<osg::ref_ptr<osg::Light> > lights;
+            lights.reserve(lightList.size());
             for (unsigned int i=0; i<lightList.size();++i)
             {
                 lights.push_back(lightList[i]->mLightSource->getLight(frameNum));