diff --git a/viewer/image_viewer/JFJochImage.cpp b/viewer/image_viewer/JFJochImage.cpp
index ed030ef0..a11db19e 100644
--- a/viewer/image_viewer/JFJochImage.cpp
+++ b/viewer/image_viewer/JFJochImage.cpp
@@ -948,4 +948,17 @@ void JFJochImage::adjustForeground(bool input) {
 
 void JFJochImage::beforeOverlayCleared() {}
 
+double JFJochImage::GetScaleFactor() const {
+    return scale_factor;
+}
 
+void JFJochImage::setZoom(double input) {
+    if (std::isfinite(input) && input > 0) {
+        scale_factor = input;
+        if (!scene())
+            return;
+        scale(input, input);
+        updateOverlay();
+        emitViewportChanged();
+    }
+}
diff --git a/viewer/image_viewer/JFJochImage.h b/viewer/image_viewer/JFJochImage.h
index 593cda04..f16ec3ec 100644
--- a/viewer/image_viewer/JFJochImage.h
+++ b/viewer/image_viewer/JFJochImage.h
@@ -131,7 +131,8 @@ public slots:
     void fitToView();
 
     void adjustForeground(bool input);
-
+    void setZoom(double input);
 public:
     explicit JFJochImage(QWidget *parent = nullptr);
+    double GetScaleFactor() const;
 };
\ No newline at end of file
diff --git a/viewer/windows/JFJochMagnifierWindow.cpp b/viewer/windows/JFJochMagnifierWindow.cpp
index 266a5056..8027652e 100644
--- a/viewer/windows/JFJochMagnifierWindow.cpp
+++ b/viewer/windows/JFJochMagnifierWindow.cpp
@@ -11,6 +11,7 @@ JFJochMagnifierWindow::JFJochMagnifierWindow(QWidget *parent)
     : JFJochHelperWindow(parent) {
     setWindowTitle("Magnifier");
     m_image = new JFJochSimpleImage(this);
+    m_image->setZoom(m_magnification);
     setCentralWidget(m_image);
     resize(320, 320);
 }
@@ -25,11 +26,13 @@ void JFJochMagnifierWindow::imageLoaded(std::shared_ptr<const JFJochReaderImage>
     auto si = std::make_shared<SimpleImage>();
     si->image = CompressedImage(image->Image(), exp.GetXPixelsNum(), exp.GetYPixelsNum());
     m_image->setImage(si);
+    m_image->setZoom(m_magnification);
     m_have_image = true;
 }
 
 void JFJochMagnifierWindow::centerAt(QPointF scenePos) {
     if (!m_have_image || !isVisible())
         return;
-    m_image->applyViewport(QTransform::fromScale(m_magnification, m_magnification), scenePos);
+    double scale = m_image->GetScaleFactor();
+    m_image->applyViewport(QTransform::fromScale(scale, scale), scenePos);
 }