diff --git a/src/cam/options.cpp b/src/cam/options.cpp
index 82acff9bbeea476d..73d81d0bc0ec6d38 100644
--- a/src/cam/options.cpp
+++ b/src/cam/options.cpp
@@ -143,7 +143,8 @@ void OptionsParser::usage()
 		};
 
 		if (option.argument != ArgumentNone) {
-			argument += std::string(" ");
+			argument += option.argument == ArgumentOptional ?
+				"=" : " ";
 			if (option.argument == ArgumentOptional)
 				argument += "[";
 			argument += option.argumentName;