diff --git a/skimage/feature/censure.py b/skimage/feature/censure.py
index cf3d543a..dbe8daf5 100644
--- a/skimage/feature/censure.py
+++ b/skimage/feature/censure.py
@@ -126,7 +126,9 @@ def keypoints_censure(image, min_scale=1, max_scale=7, mode='DoB',
     max_scale : int
         Maximum scale to extract keypoints from. The keypoints will be
         extracted from all the scales except the first and the last i.e.
-        from the scales in the range [min_scale + 1, max_scale - 1].
+        from the scales in the range [min_scale + 1, max_scale - 1]. The filter
+        sizes for different scales is such that the two adjacent scales
+        comprise of an octave.
     mode : {'DoB', 'Octagon', 'STAR'}
         Type of bi-level filter used to get the scales of the input image.
         Possible values are 'DoB', 'Octagon' and 'STAR'. The three modes
diff --git a/skimage/feature/orb.py b/skimage/feature/orb.py
index c45e0789..63586ff6 100644
--- a/skimage/feature/orb.py
+++ b/skimage/feature/orb.py
@@ -49,7 +49,7 @@ def keypoints_orb(image, n_keypoints=500, fast_n=9, fast_threshold=0.08,
         values of k result in detection of sharp corners.
     downscale : float
         Downscale factor for the image pyramid. Default value 1.2 is chosen so
-        that we have more scales per octave i.e. log1.2(2) in this case.
+        that we have more dense scales that enable robust scale invariance.
     n_scales : int
         Number of scales from the bottom of the image pyramid to extract
         the features from.