diff --git a/src/widgets/aperture_priority_page.py b/src/widgets/aperture_priority_page.py
index 0aed6c9..682d093 100644
--- a/src/widgets/aperture_priority_page.py
+++ b/src/widgets/aperture_priority_page.py
@@ -66,3 +66,7 @@ class AperturePriorityPage(Gtk.Box):
         shutterSpeed = EVCalculator.calcShutterSpeed(self.__isoSpeed, self.__sensorValue, apertureValue)
         # TODO: Round shutter speed value to nearest existing value and set label color to red if outside 1 stop range
         self.aperture_priority_time_label.set_label("1/ {:.5f}".format(shutterSpeed))
+
+    @Gtk.Template.Callback()
+    def onApertureChanged(self, dropDown: Gtk.DropDown, _: any):
+        self.updateView()
diff --git a/src/widgets/aperture_priority_page.ui b/src/widgets/aperture_priority_page.ui
index 0c4e959..af56d19 100644
--- a/src/widgets/aperture_priority_page.ui
+++ b/src/widgets/aperture_priority_page.ui
@@ -60,6 +60,7 @@
             </items>
           </object>
         </property>
+        <signal name="notify::selected-item" handler="onApertureChanged"/>
       </object>
     </child>
   </template>