diff --git a/gtsam/geometry/Cal3DS2.h b/gtsam/geometry/Cal3DS2.h
index 81463ac06..4009a1921 100644
--- a/gtsam/geometry/Cal3DS2.h
+++ b/gtsam/geometry/Cal3DS2.h
@@ -23,18 +23,11 @@
 namespace gtsam {
 
 /**
- * @brief Calibration of a camera with radial distortion
+ * @brief Calibration of a camera with radial distortion that also supports
+ * Lie-group behaviors for optimization.
+ * \sa Cal3DS2_Base
  * @addtogroup geometry
  * \nosubgrouping
- *
- * Uses same distortionmodel as OpenCV, with
- * http://docs.opencv.org/modules/calib3d/doc/camera_calibration_and_3d_reconstruction.html
- * but using only k1,k2,p1, and p2 coefficients.
- * K = [ fx s u0 ; 0 fy v0 ; 0 0 1 ]
- * rr = Pn.x^2 + Pn.y^2
- * \hat{pn} = (1 + k1*rr + k2*rr^2 ) pn + [ 2*k3 pn.x pn.y + k4 (rr + 2 Pn.x^2) ;
- *                      k3 (rr + 2 Pn.y^2) + 2*k4 pn.x pn.y  ]
- * pi = K*pn
  */
 class GTSAM_EXPORT Cal3DS2 : public Cal3DS2_Base {
 
diff --git a/gtsam/geometry/Cal3DS2_Base.h b/gtsam/geometry/Cal3DS2_Base.h
index cfbdde07c..4da5d1360 100644
--- a/gtsam/geometry/Cal3DS2_Base.h
+++ b/gtsam/geometry/Cal3DS2_Base.h
@@ -32,9 +32,9 @@ namespace gtsam {
  * but using only k1,k2,p1, and p2 coefficients.
  * K = [ fx s u0 ; 0 fy v0 ; 0 0 1 ]
  * rr = Pn.x^2 + Pn.y^2
- * \hat{pn} = (1 + k1*rr + k2*rr^2 ) pn + [ 2*k3 pn.x pn.y + k4 (rr + 2 Pn.x^2) ;
- *                      k3 (rr + 2 Pn.y^2) + 2*k4 pn.x pn.y  ]
- * pi = K*pn
+ * \hat{Pn} = (1 + k1*rr + k2*rr^2 ) Pn + [ 2*p1 Pn.x Pn.y + p2 (rr + 2 Pn.x^2) ;
+ *                      p1 (rr + 2 Pn.y^2) + 2*p2 Pn.x Pn.y  ]
+ * pi = K*Pn
  */
 class GTSAM_EXPORT Cal3DS2_Base {