diff --git a/src/ipa/libipa/agc.cpp b/src/ipa/libipa/agc.cpp
index b899f7c643..fb615f0af2 100644
--- a/src/ipa/libipa/agc.cpp
+++ b/src/ipa/libipa/agc.cpp
@@ -442,14 +442,19 @@ void fillMissing(AgcMeanLuminance::Configuration &config)
 {
 	/*
 	 * If we don't have any exposure modes in the tuning data we create an
-	 * ExposureModeHelper using an empty vector of stages. This will result
-	 * in the ExposureModeHelper simply driving the exposure time as high as
-	 * possible before touching gain.
+	 * ExposureModeHelper using a single stage of effectively unlimited exposure
+	 * and gain. This will result in the ExposureModeHelper simply driving the
+	 * exposure time as high as possible before touching gain.
 	 */
 	if (config.exposureModeHelpers.empty())
 		config.exposureModeHelpers.try_emplace(
 			controls::ExposureMaximize,
-			std::vector<ExposureModeHelper::Stage>{});
+			std::vector{
+				ExposureModeHelper::Stage{
+					.exposureTime = utils::Duration::max(),
+					.gain = std::numeric_limits<double>::max(),
+				},
+			});
 
 	/*
 	 * If the tuning data file contains no constraints then we use the
diff --git a/src/ipa/libipa/exposure_mode_helper.cpp b/src/ipa/libipa/exposure_mode_helper.cpp
index 8a712c6da9..4123f73cc8 100644
--- a/src/ipa/libipa/exposure_mode_helper.cpp
+++ b/src/ipa/libipa/exposure_mode_helper.cpp
@@ -84,6 +84,7 @@ ExposureModeHelper::ExposureModeHelper(std::vector<Stage> &&stages)
 	: stages_(std::move(stages)), lineDuration_(1us), minExposureTime_(0us),
 	  maxExposureTime_(0us), minGain_(0), maxGain_(0), sensorHelper_(nullptr)
 {
+	ASSERT(!stages_.empty());
 }
 
 /**
@@ -203,8 +204,8 @@ double ExposureModeHelper::clampGain(double gain, double *quantizationGain) cons
  * value.
  *
  * If no combination of exposure time and gain limits is found that meets the
- * required exposure, the helper falls-back to simply maximising the exposure
- * time first, followed by analogue gain, followed by digital gain.
+ * required exposure, then the exposure and gain of the last stage will be used,
+ * and the digital gain will be increased as necessary.
  *
  * During the calculations the gain missed due to quantization is recorded and
  * returned as quantization gain. The quantization gain is not included in the
@@ -280,14 +281,11 @@ ExposureModeHelper::splitExposure(utils::Duration exposure) const
 	}
 
 	/*
-	 * From here on all we can do is max out the exposure time, followed by
-	 * the analogue gain. If we still haven't achieved the target we send
-	 * the rest of the exposure time to digital gain. If we were given no
-	 * stages to use then the default gain of 1.0 is used so that exposure
-	 * time is maxed before gain is touched at all.
+	 * If no stages could satisfy the desired exposure, then use the last
+	 * stage's exposure time and gain.
 	 */
-	exposureTime = clampExposureTime(exposure / lastStageGain, &quantGain);
-	gain = clampGain(exposure / exposureTime, &quantGain2);
+	exposureTime = clampExposureTime(stages_.back().exposureTime, &quantGain);
+	gain = clampGain(stages_.back().gain, &quantGain2);
 	quantGain *= quantGain2;
 
 	return { exposureTime, gain, quantGain,