diff --git a/android-project/app/src/main/java/com/photobooth/app/MainActivity.kt b/android-project/app/src/main/java/com/photobooth/app/MainActivity.kt
index f5ed4f8..165b610 100644
--- a/android-project/app/src/main/java/com/photobooth/app/MainActivity.kt
+++ b/android-project/app/src/main/java/com/photobooth/app/MainActivity.kt
@@ -89,8 +89,8 @@ class MainActivity : AppCompatActivity() {
 
     private fun updateBackgroundMode() {
         currentBackgroundMode = when {
-            selectedBgAssetPath != null -> BackgroundMode.AI_BLUR
-            blurIntensity > 0f || isPortraitBlurModeOpen -> BackgroundMode.HARDWARE_DOF
+            selectedBgAssetPath != null || blurIntensity > 0f -> BackgroundMode.AI_BLUR
+            isPortraitBlurModeOpen -> BackgroundMode.HARDWARE_DOF
             else -> BackgroundMode.DEFAULT
         }
     }
@@ -1090,6 +1090,7 @@ class MainActivity : AppCompatActivity() {
     private fun setCurrentAttributeValue(value: Float) {
         if (currentAttribute == EditAttribute.PORTRAIT_BLUR) {
             blurIntensity = value.coerceIn(0f, 1f)
+            updateBackgroundMode()
             return
         }
         if (currentAttribute == EditAttribute.BG_REPLACE) return
@@ -1767,13 +1768,6 @@ class MainActivity : AppCompatActivity() {
                         cachedMaskHeight = h
                         categoryMaskBuffer.rewind()
                         
-                        // Ở chế độ Portrait Blur thấu kính vật lý (selectedBgAssetPath == null),
-                        // sau khi đã lưu cache mask để hỗ trợ xác định đối tượng chạm,
-                        // ta bỏ qua hoàn toàn việc tạo mặt nạ alpha và làm mờ phông nền nhân tạo.
-                        if (selectedBgAssetPath == null) {
-                            return capturedImage
-                        }
-                        
                         // Create and blur alpha mask with Touch-to-Focus class selection
                         val focusClassId = if (userSelectedClassFocus >= 0) userSelectedClassFocus else -1
                         val alphaMask = FloatArray(w * h)
@@ -1815,8 +1809,8 @@ class MainActivity : AppCompatActivity() {
                         val bgPixels = IntArray(w * h)
                         var blurredBg: android.graphics.Bitmap? = null
                         if (blurIntensity > 0f) {
-                            val opticalIntensity = Math.pow(blurIntensity.toDouble(), 2.5).toFloat()
-                            val radius = (25 * opticalIntensity).toInt().coerceIn(1, 25)
+                            val maxRadius = if (w <= 480) 15f else 75f
+                            val radius = (2f + blurIntensity * maxRadius).toInt().coerceIn(1, 120)
                             blurredBg = blurBitmap(baseBg, radius)
                             blurredBg.getPixels(bgPixels, 0, w, 0, 0, w, h)
                         } else {
@@ -1943,8 +1937,8 @@ class MainActivity : AppCompatActivity() {
                     val bgPixels = IntArray(w * h)
                     var blurredBg: android.graphics.Bitmap? = null
                     if (blurIntensity > 0f) {
-                        val opticalIntensity = Math.pow(blurIntensity.toDouble(), 2.5).toFloat()
-                        val radius = (40 * opticalIntensity).toInt().coerceIn(1, 40)
+                        val maxRadius = if (w <= 480) 15f else 75f
+                        val radius = (2f + blurIntensity * maxRadius).toInt().coerceIn(1, 120)
                         blurredBg = blurBitmap(baseBg, radius)
                         blurredBg.getPixels(bgPixels, 0, w, 0, 0, w, h)
                     } else {
@@ -2381,8 +2375,8 @@ class MainActivity : AppCompatActivity() {
         val bgPixels = IntArray(w * h)
         var blurredBg: android.graphics.Bitmap? = null
         if (blurIntensity > 0f) {
-            val opticalIntensity = Math.pow(blurIntensity.toDouble(), 2.5).toFloat()
-            val radius = (40 * opticalIntensity).toInt().coerceIn(1, 40)
+            val maxRadius = if (w <= 480) 15f else 75f
+            val radius = (2f + blurIntensity * maxRadius).toInt().coerceIn(1, 120)
             blurredBg = blurBitmap(baseBg, radius)
             blurredBg.getPixels(bgPixels, 0, w, 0, 0, w, h)
         } else {