diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt
index 85d63532a3..2393f17efc 100644
--- a/Documentation/pretty-formats.txt
+++ b/Documentation/pretty-formats.txt
@@ -79,7 +79,10 @@ stored in the commit object.  Notably, the SHA-1s are
 displayed in full, regardless of whether --abbrev or
 --no-abbrev are used, and 'parents' information show the
 true parent commits, without taking grafts or history
-simplification into account.
+simplification into account. Note that this format affects the way
+commits are displayed, but not the way the diff is shown e.g. with
+`git log --raw`. To get full object names in a raw diff format,
+use `--no-abbrev`.
 
 * 'format:<string>'
 +