diff --git a/mlx_lm/convert.py b/mlx_lm/convert.py
index ed8e97d..ab3fc62 100644
--- a/mlx_lm/convert.py
+++ b/mlx_lm/convert.py
@@ -86,8 +86,8 @@ def convert(
     hf_path: str,
     mlx_path: str = "mlx_model",
     quantize: bool = False,
-    q_group_size: int = 64,
-    q_bits: int = 4,
+    q_group_size: Optional[int] = None,
+    q_bits: Optional[int] = None,
     q_mode: str = "affine",
     dtype: Optional[str] = None,
     upload_repo: str = None,