diff --git a/backend/genesys/gl843.cpp b/backend/genesys/gl843.cpp
index 2f4934954..4efa82b27 100644
--- a/backend/genesys/gl843.cpp
+++ b/backend/genesys/gl843.cpp
@@ -969,14 +969,21 @@ static void gl843_init_optical_regs_scan(Genesys_Device* dev, const Genesys_Sens
         r->value |= REG_0x01_DVDSET;
     }
 
-    bool use_shdarea = dpihw > 600;
+    bool use_shdarea = false;
     if (dev->model->model_id == ModelId::CANON_4400F) {
         use_shdarea = session.params.xres <= 600;
     } else if (dev->model->model_id == ModelId::CANON_8400F) {
         use_shdarea = session.params.xres <= 400;
-    } else if (dev->model->model_id == ModelId::CANON_8600F) {
+    } else if (dev->model->model_id == ModelId::CANON_8600F ||
+               dev->model->model_id == ModelId::PLUSTEK_OPTICFILM_7200I ||
+               dev->model->model_id == ModelId::PLUSTEK_OPTICFILM_7300 ||
+               dev->model->model_id == ModelId::PLUSTEK_OPTICFILM_7500I)
+    {
         use_shdarea = true;
+    } else {
+        use_shdarea = session.params.xres > 600;
     }
+
     if (use_shdarea) {
         r->value |= REG_0x01_SHDAREA;
     } else {