diff --git a/src/ipa/raspberrypi/controller/rpi/lux.cpp b/src/ipa/raspberrypi/controller/rpi/lux.cpp
index aefd92d4..f74381ca 100644
--- a/src/ipa/raspberrypi/controller/rpi/lux.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/lux.cpp
@@ -46,6 +46,11 @@ void Lux::Read(boost::property_tree::ptree const &params)
 	current_aperture_ = reference_aperture_;
 }
 
+void Lux::SetCurrentAperture(double aperture)
+{
+	current_aperture_ = aperture;
+}
+
 void Lux::Prepare(Metadata *image_metadata)
 {
 	std::unique_lock<std::mutex> lock(mutex_);
diff --git a/src/ipa/raspberrypi/controller/rpi/lux.hpp b/src/ipa/raspberrypi/controller/rpi/lux.hpp
index 7b6c7258..f9090484 100644
--- a/src/ipa/raspberrypi/controller/rpi/lux.hpp
+++ b/src/ipa/raspberrypi/controller/rpi/lux.hpp
@@ -6,7 +6,6 @@
  */
 #pragma once
 
-#include <atomic>
 #include <mutex>
 
 #include "../lux_status.h"
@@ -34,7 +33,7 @@ private:
 	double reference_aperture_; // units of 1/f
 	double reference_Y_; // out of 65536
 	double reference_lux_;
-	std::atomic<double> current_aperture_;
+	double current_aperture_;
 	LuxStatus status_;
 	std::mutex mutex_;
 };