diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index d373bdda..a22a63dd 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -35,6 +35,7 @@ SET( LIBEXIV2_PRIVATE_HDR cr2image_int.hpp
                           nikonmn_int.hpp
                           orfimage_int.hpp
                           panasonicmn_int.hpp
+                          pentaxmn_int.hpp
                           pngchunk_int.hpp
                           rcsid_int.hpp
                           rw2image_int.hpp
@@ -68,7 +69,6 @@ SET( LIBEXIV2_HDR         basicio.hpp
                           mrwimage.hpp
                           olympusmn.hpp
                           orfimage.hpp
-                          pentaxmn.hpp
                           pgfimage.hpp
                           pngimage.hpp
                           preview.hpp
diff --git a/src/pentaxmn.cpp b/src/pentaxmn.cpp
index 58ae8ef6..9b1cf4b1 100644
--- a/src/pentaxmn.cpp
+++ b/src/pentaxmn.cpp
@@ -35,7 +35,7 @@ EXIV2_RCSID("@(#) $Id$")
 // *****************************************************************************
 // included header files
 #include "types.hpp"
-#include "pentaxmn.hpp"
+#include "pentaxmn_int.hpp"
 #include "value.hpp"
 #include "i18n.h"                // NLS support.
 
@@ -49,6 +49,7 @@ EXIV2_RCSID("@(#) $Id$")
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
+    namespace Internal {
 
     //! ShootingMode, tag 0x0001
     extern const TagDetails pentaxShootingMode[] = {
@@ -1129,4 +1130,4 @@ namespace Exiv2 {
         return tagInfo_;
     }
 
-}                                       // namespace Exiv2
+}}                                       // namespace Internal, Exiv2
diff --git a/src/pentaxmn.hpp b/src/pentaxmn_int.hpp
similarity index 95%
rename from src/pentaxmn.hpp
rename to src/pentaxmn_int.hpp
index 01eab382..75199f65 100644
--- a/src/pentaxmn.hpp
+++ b/src/pentaxmn_int.hpp
@@ -19,7 +19,7 @@
  * Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
  */
 /*!
-  @file    pentaxmn.hpp
+  @file    pentaxmn_int.hpp
   @brief   Pentax MakerNote implemented according to the specification
            http://www.gvsoft.homedns.org/exif/makernote-pentax-type3.html and
            based on ExifTool implementation and
@@ -29,8 +29,8 @@
            <a href="mailto:michal@cihar.com">michal@cihar.com</a>
   @date    27-Sep-07
  */
-#ifndef PENTAXMN_HPP_
-#define PENTAXMN_HPP_
+#ifndef PENTAXMN_INT_HPP_
+#define PENTAXMN_INT_HPP_
 
 // *****************************************************************************
 // included header files
@@ -46,12 +46,13 @@
 // *****************************************************************************
 // namespace extensions
 namespace Exiv2 {
+    namespace Internal {
 
 // *****************************************************************************
 // class definitions
 
     //! MakerNote for Pentaxfilm cameras
-    class EXIV2API PentaxMakerNote {
+    class PentaxMakerNote {
     public:
         //! Return read-only list of built-in Pentaxfilm tags
         static const TagInfo* tagList();
@@ -119,6 +120,6 @@ namespace Exiv2 {
 //! Shortcut for the printCombiTag template which requires typing the array name only once.
 #define EXV_PRINT_COMBITAG_MULTI(array, count, ignoredcount, ignoredcountmax) printCombiTag<EXV_COUNTOF(array), array, count, ignoredcount, ignoredcountmax>
 
-}                                       // namespace Exiv2
+}}                                      // namespace Internal, Exiv2
 
-#endif                                  // #ifndef PENTAXMN_HPP_
+#endif                                  // #ifndef PENTAXMN_INT_HPP_
diff --git a/src/tags.cpp b/src/tags.cpp
index b396051c..aa4993a9 100644
--- a/src/tags.cpp
+++ b/src/tags.cpp
@@ -43,7 +43,7 @@ EXIV2_RCSID("@(#) $Id$")
 #include "nikonmn_int.hpp"
 #include "olympusmn.hpp"
 #include "panasonicmn_int.hpp"
-#include "pentaxmn.hpp"
+#include "pentaxmn_int.hpp"
 #include "sigmamn.hpp"
 #include "sonymn.hpp"
 #include "i18n.h"                // NLS support.