diff --git a/src/Canvas.cc b/src/Canvas.cc
index 93f0329..cb0f62c 100644
--- a/src/Canvas.cc
+++ b/src/Canvas.cc
@@ -401,7 +401,7 @@ NAN_METHOD(Canvas::StreamPNGSync) {
 
     if (!args[2]->StrictEquals(NanUndefined())) {
       if (args[2]->IsUint32()) {
-        filter = args[1]->Uint32Value();
+        filter = args[2]->Uint32Value();
       } else {
         return NanThrowTypeError("Invalid filter value.");
       }