diff --git a/magick/fx.c b/magick/fx.c
index 6f9cdfc..ba873f3 100644
--- a/magick/fx.c
+++ b/magick/fx.c
@@ -2278,9 +2278,7 @@
         {
           alpha=FxEvaluateSubexpression(fx_info,channel,x,y,expression+4,beta,
             exception);
-          if (alpha == 0.0)
-            return((MagickRealType) (MagickPI/4.0));
-          gamma=(MagickRealType) (j1((double) (MagickPI*alpha))/
+          gamma=(MagickRealType) (2.0*j1((double) (MagickPI*alpha))/
             (MagickPI*alpha));
           return(gamma);
         }