Manual head focus stuck.

Manual lens refers to a lens that can only focus manually, but not automatically. Although this kind of lens focusing is relatively troublesome and difficult for beginners to master, it is very popular with photographers and professional users because of its unique focusing control and precise focusing state once focusing is successful.

Because the manual lens requires the user to manually operate the focus ring to focus, it is definitely more difficult than the autofocus lens that can complete the focus operation by half pressing the shutter.