diff --git a/dcimg.py b/dcimg.py
index 601e99c..a221d8e 100644
--- a/dcimg.py
+++ b/dcimg.py
@@ -398,7 +398,8 @@ def _parse_header(self):
             if binning_x != binning_y:
                 raise ValueError('different binning in X and Y')
 
-            self.binning = binning_x
+            if binning_x > 0:
+                self.binning = binning_x
 
         if self.byte_depth != 1 and self.byte_depth != 2:
             raise ValueError(