diff --git a/hgext/convert/__init__.py b/hgext/convert/__init__.py
--- a/hgext/convert/__init__.py
+++ b/hgext/convert/__init__.py
@@ -300,6 +300,11 @@ def convert(ui, src, dest=None, revmapfi
         be imported as a rename if more than 90% of the file hasn't
         changed. The default is ``0``.
 
+    :convert.git.findcopiesharder: while detecting copies, look at all
+        files in the working copy instead of just changed ones. This
+        is very expensive for large projects, and is only effective when
+        ``convert.git.similarity`` is greater than 0. The default is False.
+
     Perforce Source
     ###############
 
diff --git a/hgext/convert/git.py b/hgext/convert/git.py
--- a/hgext/convert/git.py
+++ b/hgext/convert/git.py
@@ -102,6 +102,10 @@ class convert_git(converter_source):
             raise util.Abort(_('similarity must be between 0 and 100'))
         if similarity > 0:
             self.simopt = '--find-copies=%d%%' % similarity
+            findcopiesharder = ui.configbool('convert', 'git.findcopiesharder',
+                                             False)
+            if findcopiesharder:
+                self.simopt += ' --find-copies-harder'
         else:
             self.simopt = ''
 
diff --git a/tests/test-convert-git.t b/tests/test-convert-git.t
--- a/tests/test-convert-git.t
+++ b/tests/test-convert-git.t
@@ -277,6 +277,18 @@ input validation
     foo
   R foo
 
+  $ cd git-repo2
+  $ cp bar bar-copied2
+  $ git add bar-copied2
+  $ commit -a -m 'copy with no changes'
+  $ cd ..
+
+  $ hg -q convert --config convert.git.similarity=100 \
+  > --config convert.git.findcopiesharder=1 --datesort git-repo2 fullrepo
+  $ hg -R fullrepo status -C --change master
+  A bar-copied2
+    bar
+
 test binary conversion (issue1359)
 
   $ count=19
diff --git a/tests/test-convert.t b/tests/test-convert.t
--- a/tests/test-convert.t
+++ b/tests/test-convert.t
@@ -253,6 +253,12 @@
                     "90" means that a delete/add pair will be imported as a
                     rename if more than 90% of the file hasn't changed. The
                     default is "0".
+      convert.git.findcopiesharder
+                    while detecting copies, look at all files in the working
+                    copy instead of just changed ones. This is very expensive
+                    for large projects, and is only effective when
+                    "convert.git.similarity" is greater than 0. The default is
+                    False.
   
       Perforce Source
       ###############