diff --git a/CHANGELOG.md b/CHANGELOG.md
index 85a58e18..bd3e1a2b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
 - (pro) Use PNG quantization for very low-complexity images when the `best` format is used.
 
 ### Fixed
+- Fix blur and sharpen performance for images with alpha channel.
 - (pro) Fix object detecttion accuracy.
 
 ## [3.27.0] - 2024-12-18
diff --git a/vips/vips.c b/vips/vips.c
index b9fe92de..971d62e6 100644
--- a/vips/vips.c
+++ b/vips/vips.c
@@ -609,7 +609,7 @@ vips_apply_filters(VipsImage *in, VipsImage **out, double blur_sigma,
       return 1;
     }
 
-    in = t[0];
+    in = t[1];
     premultiplied = TRUE;
   }