diff --git a/ObservationSim/ObservationSim.py b/ObservationSim/ObservationSim.py
index 68b4d3d57178c8554b85d9600c4361ca02eb9a31..2f19116fc1099d465036effe8a34a30a6a1a9b9e 100755
--- a/ObservationSim/ObservationSim.py
+++ b/ObservationSim/ObservationSim.py
@@ -239,7 +239,7 @@ class Observation(object):
                 try:
                     if self.config["run_option"]["out_cat_only"]:
                         isUpdated = True
-                    if chip.survey_type == "photometric" and not self.config["run_option"]["out_cat_only"]:
+                    elif chip.survey_type == "photometric" and not self.config["run_option"]["out_cat_only"]:
                         isUpdated, pos_shear = obj.drawObj_multiband(
                             tel=self.tel,
                             pos_img=pos_img,