diff --git a/camera/camera.py b/camera/camera.py
index a06791a3..37198bf0 100644
--- a/camera/camera.py
+++ b/camera/camera.py
@@ -300,7 +300,7 @@ class Camera(object):
         ctx.set_matrix(cairo.Matrix(
             fdiv(pw, fw), 0,
             0, -fdiv(ph, fh),
-            (pw / 2) + fc[0] * fdiv(pw, fw),
+            (pw / 2) - fc[0] * fdiv(pw, fw),
             (ph / 2) + fc[1] * fdiv(ph, fh),
         ))
         self.cache_cairo_context(pixel_array, ctx)