diff --git a/meanas/fdmath/operators.py b/meanas/fdmath/operators.py
index b5cd8fc..5d50670 100644
--- a/meanas/fdmath/operators.py
+++ b/meanas/fdmath/operators.py
@@ -34,7 +34,7 @@ def shift_circ(
     if axis not in range(len(shape)):
         raise Exception(f'Invalid direction: {axis}, shape is {shape}')
 
-    shifts = [abs(shift_distance) if a == axis else 0 for a in range(3)]
+    shifts = [abs(shift_distance) if a == axis else 0 for a in range(len(shape))]
     shifted_diags = [(numpy.arange(n) + s) % n for n, s in zip(shape, shifts, strict=True)]
     ijk = numpy.meshgrid(*shifted_diags, indexing='ij')
 
@@ -82,7 +82,7 @@ def shift_with_mirror(
         v = numpy.where(v < 0, - 1 - v, v)
         return v
 
-    shifts = [shift_distance if a == axis else 0 for a in range(3)]
+    shifts = [shift_distance if a == axis else 0 for a in range(len(shape))]
     shifted_diags = [mirrored_range(n, s) for n, s in zip(shape, shifts, strict=True)]
     ijk = numpy.meshgrid(*shifted_diags, indexing='ij')