diff --git a/src/cli/test.py b/src/cli/test.py
index 21cb2db..dbcd06d 100644
--- a/src/cli/test.py
+++ b/src/cli/test.py
@@ -183,7 +183,7 @@ try:
 
 		# Delay the frame if slowmode is on
 		if slow_mode:
-			time.sleep(.5 - frame_time)
+			time.sleep(max([.5 - frame_time, 0.0]))
 
 		if exposure != -1:
 			# For a strange reason on some cameras (e.g. Lenoxo X1E)