diff --git a/esbo_etc/classes/optical_component/BeamSplitter.py b/esbo_etc/classes/optical_component/BeamSplitter.py
index d993902..bb9b445 100644
--- a/esbo_etc/classes/optical_component/BeamSplitter.py
+++ b/esbo_etc/classes/optical_component/BeamSplitter.py
@@ -11,7 +11,7 @@ class BeamSplitter(AHotOpticalComponent):
     A class to model the optical characteristics of a beam splitter.
     """
     @u.quantity_input(temp=[u.Kelvin, u.Celsius], obstructor_temp=[u.Kelvin, u.Celsius])
-    def __init__(self, parent: IRadiant, transmittance: str, emissivity: Union[str, float] = 1,
+    def __init__(self, parent: IRadiant, transmittance: str, emissivity: Union[str, float] = None,
                  temp: u.Quantity = 0 * u.K, obstruction: float = 0, obstructor_temp: u.Quantity = 0 * u.K,
                  obstructor_emissivity: float = 1):
         """
@@ -37,7 +37,12 @@ class BeamSplitter(AHotOpticalComponent):
         obstructor_emissivity : float
             Emissivity of the obstructing component.
         """
-        self._transmittance = SpectralQty.fromFile(transmittance, u.nm, u.dimensionless_unscaled)
+        try:
+            self._transmittance = float(transmittance) * u.dimensionless_unscaled
+        except ValueError:
+            self._transmittance = SpectralQty.fromFile(transmittance, u.nm, u.dimensionless_unscaled)
+        if emissivity is None:
+            emissivity = -1 * self._transmittance + 1.0
         super().__init__(parent, emissivity, temp, obstruction, obstructor_temp, obstructor_emissivity)
 
     def _propagate(self, rad: SpectralQty) -> SpectralQty:
@@ -73,7 +78,9 @@ class BeamSplitter(AHotOpticalComponent):
         """
         mes = conf.check_file("transmittance")
         if mes is not None:
-            return mes
+            mes = conf.check_float("transmittance")
+            if mes is not None:
+                return mes
         if hasattr(conf, "emissivity"):
             mes = conf.check_file("emissivity")
             if mes is not None:
diff --git a/esbo_etc/classes/optical_component/Filter.py b/esbo_etc/classes/optical_component/Filter.py
index 7ff3ba0..a854d55 100644
--- a/esbo_etc/classes/optical_component/Filter.py
+++ b/esbo_etc/classes/optical_component/Filter.py
@@ -104,7 +104,7 @@ class Filter(AHotOpticalComponent):
                                obstructor_temp, obstructor_emissivity)
 
     # @u.quantity_input(temp=[u.Kelvin, u.Celsius], obstructor_temp=[u.Kelvin, u.Celsius])
-    def _fromFile(self, parent: IRadiant, transmittance: str, emissivity: Union[str, float] = 1,
+    def _fromFile(self, parent: IRadiant, transmittance: str, emissivity: Union[str, float] = None,
                   temp: u.Quantity = 0 * u.K, obstruction: float = 0, obstructor_temp: u.Quantity = 0 * u.K,
                   obstructor_emissivity: float = 1) -> dict:
         """
@@ -136,7 +136,13 @@ class Filter(AHotOpticalComponent):
         args : dict
             The arguments for the class instantiation.
         """
-        return {"parent": parent, "transmittance": SpectralQty.fromFile(transmittance, u.nm, u.dimensionless_unscaled),
+        try:
+            _transmittance = float(transmittance) * u.dimensionless_unscaled
+        except ValueError:
+            _transmittance = SpectralQty.fromFile(transmittance, u.nm, u.dimensionless_unscaled)
+        if emissivity is None:
+            emissivity = -1 * _transmittance + 1.0
+        return {"parent": parent, "transmittance": _transmittance,
                 "emissivity": emissivity, "temp": temp, "obstruction": obstruction, "obstructor_temp": obstructor_temp,
                 "obstructor_emissivity": obstructor_emissivity}
 
@@ -235,6 +241,8 @@ class Filter(AHotOpticalComponent):
             mes = conf.check_selection("band", ["U", "B", "V", "R", "I", "J", "H", "K", "L", "M", "N"])
         elif hasattr(conf, "transmittance"):
             mes = conf.check_file("transmittance")
+            if mes is not None:
+                mes = conf.check_float("transmittance")
         elif hasattr(conf, "start") and hasattr(conf, "end"):
             mes = conf.check_quantity("start", u.m)
             if mes is not None:
diff --git a/esbo_etc/classes/optical_component/Lens.py b/esbo_etc/classes/optical_component/Lens.py
index 26b392f..1a99a22 100644
--- a/esbo_etc/classes/optical_component/Lens.py
+++ b/esbo_etc/classes/optical_component/Lens.py
@@ -11,7 +11,7 @@ class Lens(AHotOpticalComponent):
     A class to model the optical characteristics of a lens.
     """
     @u.quantity_input(temp=[u.Kelvin, u.Celsius], obstructor_temp=[u.Kelvin, u.Celsius])
-    def __init__(self, parent: IRadiant, transmittance: str, emissivity: Union[str, float] = 1,
+    def __init__(self, parent: IRadiant, transmittance: str, emissivity: Union[str, float] = None,
                  temp: u.Quantity = 0 * u.K, obstruction: float = 0, obstructor_temp: u.Quantity = 0 * u.K,
                  obstructor_emissivity: float = 1):
         """
@@ -37,7 +37,12 @@ class Lens(AHotOpticalComponent):
         obstructor_emissivity : float
             Emissivity of the obstructing component.
         """
-        self._transmittance = SpectralQty.fromFile(transmittance, u.nm, u.dimensionless_unscaled)
+        try:
+            self._transmittance = float(transmittance) * u.dimensionless_unscaled
+        except ValueError:
+            self._transmittance = SpectralQty.fromFile(transmittance, u.nm, u.dimensionless_unscaled)
+        if emissivity is None:
+            emissivity = -1 * self._transmittance + 1.0
         super().__init__(parent, emissivity, temp, obstruction, obstructor_temp, obstructor_emissivity)
 
     def _propagate(self, rad: SpectralQty) -> SpectralQty:
@@ -73,7 +78,9 @@ class Lens(AHotOpticalComponent):
         """
         mes = conf.check_file("transmittance")
         if mes is not None:
-            return mes
+            mes = conf.check_float("transmittance")
+            if mes is not None:
+                return mes
         if hasattr(conf, "emissivity"):
             mes = conf.check_file("emissivity")
             if mes is not None:
diff --git a/esbo_etc/classes/optical_component/Mirror.py b/esbo_etc/classes/optical_component/Mirror.py
index 5fdea4c..f576530 100644
--- a/esbo_etc/classes/optical_component/Mirror.py
+++ b/esbo_etc/classes/optical_component/Mirror.py
@@ -11,7 +11,7 @@ class Mirror(AHotOpticalComponent):
     A class to model the optical characteristics of a mirror.
     """
     @u.quantity_input(temp=[u.Kelvin, u.Celsius], obstructor_temp=[u.Kelvin, u.Celsius])
-    def __init__(self, parent: IRadiant, reflectance: str, emissivity: Union[str, float] = 1,
+    def __init__(self, parent: IRadiant, reflectance: str, emissivity: Union[str, float] = None,
                  temp: u.Quantity = 0 * u.K, obstruction: float = 0, obstructor_temp: u.Quantity = 0 * u.K,
                  obstructor_emissivity: float = 1):
         """
@@ -37,7 +37,12 @@ class Mirror(AHotOpticalComponent):
         obstructor_emissivity : float
             Emissivity of the obstructing component.
         """
-        self._reflectance = SpectralQty.fromFile(reflectance, u.nm, u.dimensionless_unscaled)
+        try:
+            self._reflectance = float(reflectance) * u.dimensionless_unscaled
+        except ValueError:
+            self._reflectance = SpectralQty.fromFile(reflectance, u.nm, u.dimensionless_unscaled)
+        if emissivity is None:
+            emissivity = -1 * self._reflectance + 1.0
         super().__init__(parent, emissivity, temp, obstruction, obstructor_temp, obstructor_emissivity)
 
     def _propagate(self, rad: SpectralQty) -> SpectralQty:
@@ -73,7 +78,9 @@ class Mirror(AHotOpticalComponent):
         """
         mes = conf.check_file("reflectance")
         if mes is not None:
-            return mes
+            mes = conf.check_float("reflectance")
+            if mes is not None:
+                return mes
         if hasattr(conf, "emissivity"):
             mes = conf.check_file("emissivity")
             if mes is not None: