diff --git a/stretchtoolbar.cpp b/stretchtoolbar.cpp
index 2e74e99..1e4034d 100644
--- a/stretchtoolbar.cpp
+++ b/stretchtoolbar.cpp
@@ -48,14 +48,16 @@ void StretchToolbar::stretchImage(Image *img)
     {
         if(img->rawImage())
         {
-            double median, mad;
-            img->rawImage()->imageStats(nullptr, nullptr, &median, nullptr, nullptr, &mad);
+            double median, mad, max;
+            img->rawImage()->imageStats(nullptr, nullptr, &median, nullptr, &max, &mad);
             median /= img->rawImage()->norm();
             mad /= img->rawImage()->norm();
+            max /= img->rawImage()->norm();
+            if(max>1.0f)max = 1.0f;
             float bp = median + mad * BLACK_POINT_SIGMA * MAD_TO_SIGMA;
             float mid = MTF(median - bp, TARGET_BACKGROUND);
-            m_stfSlider->setMTFParams(bp, mid, 1.0f);
-            emit paramChanged(m_stfSlider->blackPoint(), m_stfSlider->midPoint(), 1.0f);
+            m_stfSlider->setMTFParams(bp, mid, max);
+            emit paramChanged(m_stfSlider->blackPoint(), m_stfSlider->midPoint(), max);
         }
     }
 }