diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e7017d71..bc37b5eb 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -40,6 +40,7 @@ SET( LIBEXIV2_PRIVATE_HDR cr2image_int.hpp
                           rcsid_int.hpp
                           rw2image_int.hpp
                           sigmamn_int.hpp
+                          sonymn_int.hpp
                           tiffcomposite_int.hpp
                           tifffwd_int.hpp
                           tiffimage_int.hpp
@@ -77,7 +78,6 @@ SET( LIBEXIV2_HDR         basicio.hpp
                           psdimage.hpp
                           rafimage.hpp
                           rw2image.hpp
-                          sonymn.hpp
                           tags.hpp
                           tgaimage.hpp
                           tiffimage.hpp
diff --git a/src/sonymn.cpp b/src/sonymn.cpp
index 36d4459a..de71509c 100644
--- a/src/sonymn.cpp
+++ b/src/sonymn.cpp
@@ -32,7 +32,7 @@ EXIV2_RCSID("@(#) $Id$")
 // included header files
 #include "types.hpp"
 #include "minoltamn.hpp"
-#include "sonymn.hpp"
+#include "sonymn_int.hpp"
 #include "value.hpp"
 #include "i18n.h"                // NLS support.
 
@@ -46,6 +46,7 @@ EXIV2_RCSID("@(#) $Id$")
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
+    namespace Internal {
 
     // -- Standard Sony Makernotes tags ---------------------------------------------------------------
 
@@ -724,4 +725,4 @@ namespace Exiv2 {
         return tagInfoCs2_;
     }
 
-}                                       // namespace Exiv2
+}}                                      // namespace Internal, Exiv2
diff --git a/src/sonymn.hpp b/src/sonymn_int.hpp
similarity index 91%
rename from src/sonymn.hpp
rename to src/sonymn_int.hpp
index ecf86753..45335d61 100644
--- a/src/sonymn.hpp
+++ b/src/sonymn_int.hpp
@@ -19,7 +19,7 @@
  * Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
  */
 /*!
-  @file    sonymn.hpp
+  @file    sonymn_int.hpp
   @brief   Sony MakerNote implemented using the following references:<br>
            <a href="http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/Sony.html">Sony Makernote list</a> by Phil Harvey<br>
 Email communication with <a href="mailto:caulier dot gilles at gmail dot com">caulier dot gilles at gmail dot com</a><br>
@@ -31,8 +31,8 @@ Email communication with <a href="mailto:caulier dot gilles at gmail dot com">ca
            <a href="mailto:caulier dot gilles at gmail dot com">caulier dot gilles at gmail dot com</a>
   @date    18-Apr-05, ahu: created
  */
-#ifndef SONYMN_HPP_
-#define SONYMN_HPP_
+#ifndef SONYMN_INT_HPP_
+#define SONYMN_INT_HPP_
 
 // *****************************************************************************
 // included header files
@@ -46,12 +46,13 @@ Email communication with <a href="mailto:caulier dot gilles at gmail dot com">ca
 // *****************************************************************************
 // namespace extensions
 namespace Exiv2 {
+    namespace Internal {
 
 // *****************************************************************************
 // class definitions
 
     //! MakerNote for Sony cameras
-    class EXIV2API SonyMakerNote {
+    class SonyMakerNote {
     public:
         //! Return read-only list of built-in Sony tags
         static const TagInfo* tagList();
@@ -74,6 +75,7 @@ namespace Exiv2 {
         static const TagInfo tagInfoCs2_[];
 
     }; // class SonyMakerNote
-}                                       // namespace Exiv2
 
-#endif                                  // #ifndef SONYMN_HPP_
+}}                                      // namespace Internal, Exiv2
+
+#endif                                  // #ifndef SONYMN_INT_HPP_
diff --git a/src/tags.cpp b/src/tags.cpp
index 82292989..46ca2bd9 100644
--- a/src/tags.cpp
+++ b/src/tags.cpp
@@ -45,7 +45,7 @@ EXIV2_RCSID("@(#) $Id$")
 #include "panasonicmn_int.hpp"
 #include "pentaxmn_int.hpp"
 #include "sigmamn_int.hpp"
-#include "sonymn.hpp"
+#include "sonymn_int.hpp"
 #include "i18n.h"                // NLS support.
 
 #include <iostream>