diff --git a/picamera/camera.py b/picamera/camera.py
index 36b1202a..f815e379 100644
--- a/picamera/camera.py
+++ b/picamera/camera.py
@@ -229,6 +229,23 @@ class PiCamera(object):
             6: mo.PiSensorMode('720p', (40, 90), full_fov=False),
             7: mo.PiSensorMode('VGA', (40, 90), full_fov=False),
             },
+        # XXX guessing testc isn't the final sensor name, and these modes are
+        # probably a bit wrong (definitely the framerates which are entirely
+        # guesses!). May want to extend PiSensorMode to have a bpp field given
+        # the XGA modes beneath are definitely 10-bit and the rest are 12-bit
+        # raw? Doesn't matter for picamera operations, but useful to API users
+        'testc': {
+            1: mo.PiSensorMode('2028x1088', (1/10, 50), full_fov=False),
+            2: mo.PiSensorMode('2028x1520', (1/10, 50), still=True),
+            3: mo.PiSensorMode('4056x3040', (5/1000, 10), still=True),
+            4: mo.PiSensorMode('1012x760', (50.1, 120)),
+            },
+        'imx477': {
+            1: mo.PiSensorMode('2028x1088', (1/10, 50), full_fov=False),
+            2: mo.PiSensorMode('2028x1520', (1/10, 50), still=True),
+            3: mo.PiSensorMode('4056x3040', (5/1000, 10), still=True),
+            4: mo.PiSensorMode('1012x760', (50.1, 120)),
+            },
         }
 
     METER_MODES = {
@@ -491,6 +508,7 @@ def _init_revision(self, options):
             if revision.lower() == 'ov5647':
                 PiCamera.MAX_FRAMERATE = 90
             else:
+                # XXX is this correct for sensor testc?
                 PiCamera.MAX_FRAMERATE = 120
         self._revision = revision