diff --git a/doc/filters.texi b/doc/filters.texi
index d6c15837f2744e9678ab3e4a02974d0517a97087..267bd04a43b9b1d62b86bf0994f99f18491bb453 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -9955,13 +9955,13 @@ The order of differentiation to be applied on the scene. Must be chosen in the r
 
 @item minknorm
 The Minkowski parameter to be used for calculating the Minkowski distance. Must
-be chosen in the range [0,65535] and default value is 1. Set to 0 for getting
+be chosen in the range [0,20] and default value is 1. Set to 0 for getting
 max value instead of calculating Minkowski distance.
 
 @item sigma
 The standard deviation of Gaussian blur to be applied on the scene. Must be
-chosen in the range [0,1024.0] and default value = 1. Sigma can't be set to 0
-if @var{difford} is greater than 0.
+chosen in the range [0,1024.0] and default value = 1. floor( @var{sigma} * break_off_sigma(3) )
+can't be euqal to 0 if @var{difford} is greater than 0.
 @end table
 
 @subsection Examples
diff --git a/libavfilter/vf_colorconstancy.c b/libavfilter/vf_colorconstancy.c
index 7194688dfa028eb1691132bc53428b78afefb5c6..e8271f34ec70a3c88388ef573b55d5d660e12924 100644
--- a/libavfilter/vf_colorconstancy.c
+++ b/libavfilter/vf_colorconstancy.c
@@ -735,9 +735,9 @@ static const AVFilterPad colorconstancy_outputs[] = {
 #if CONFIG_GREYEDGE_FILTER
 
 static const AVOption greyedge_options[] = {
-    { "difford",  "set differentiation order", OFFSET(difford),  AV_OPT_TYPE_INT,    {.i64=1},   0,   2,      FLAGS },
-    { "minknorm", "set Minkowski norm",        OFFSET(minknorm), AV_OPT_TYPE_INT,    {.i64=1},   0,   65535,  FLAGS },
-    { "sigma",    "set sigma",                 OFFSET(sigma),    AV_OPT_TYPE_DOUBLE, {.dbl=1},   0.0, 1024.0, FLAGS },
+    { "difford",  "set differentiation order", OFFSET(difford),  AV_OPT_TYPE_INT,    {.i64=1}, 0,   2,      FLAGS },
+    { "minknorm", "set Minkowski norm",        OFFSET(minknorm), AV_OPT_TYPE_INT,    {.i64=1}, 0,   20,     FLAGS },
+    { "sigma",    "set sigma",                 OFFSET(sigma),    AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.0, 1024.0, FLAGS },
     { NULL }
 };