diff --git a/src/structs/quaternion.rs b/src/structs/quaternion.rs
index 52c7b26d..504066b6 100644
--- a/src/structs/quaternion.rs
+++ b/src/structs/quaternion.rs
@@ -570,24 +570,24 @@ impl<N: Arbitrary + BaseFloat> Arbitrary for UnitQuaternion<N> {
 
 impl Quaternion<f32> {
   /// Compute the exponential of a quaternion.
-  ///
-  /// This function yields a `UnitQuaternion<f32>`.
-  pub fn exp(&self) -> UnitQuaternion<f32> {
-    let v = Vector3::new(self.i, self.j, self.k);
-    let n = v.norm();
-    let z = v / n * n.sin();
-
-    UnitQuaternion::new_with_quaternion(Quaternion::new(n.cos(), z[0], z[1], z[2]))
+  pub fn exp(&self) -> Self {
+    let v = *self.vector();
+    let nn = v.norm_squared();
+    
+    if nn.is_zero() {
+      ::one()
+    } else {
+      let n = nn.sqrt();
+      let nv = v / n * n.sin();
+      Quaternion::new(n.cos(), nv.x, nv.y, nv.z)
+    }
   }
-}
 
-impl UnitQuaternion<f32> {
-  /// Compute the natural logarithm (a.k.a ln()) of a unit quaternion.
+  /// Compute the natural logarithm (a.k.a ln()) of a quaternion.
   ///
   /// Becareful, this function yields a `Quaternion<f32>`, losing the unit property.
-  pub fn log(&self) -> Quaternion<f32> {
-    let q = self.quaternion();
-    (Quaternion { w: 0., .. *q }).normalize() * q.w.acos()
+  pub fn log(&self) -> Self {
+    (Quaternion { w: 0., .. *self }).normalize() * self.w.acos()
   }
 
   /// Raise the quaternion to a given floating power.