A manual lens needs to be focused manually; Think again! The Fotodiox Pro PRONTO adapter brings autofocus to your Leica M-mount lenses. If you want to automatically focus your M-mount lenses on your Fuji X-mount camera just attach it to the PRONTO adapter. For general use, it is recommended that the lens be set to infinity focus allowing autofocus within the entire focusing range of the lens. Half-press the shutter button to activate AF and the PRONTO adapter will focus your lens just like any other AF lens. Performance is optimal with 50mm and wider lenses. Telephoto optics may require coarse manual focusing before use of the adapter for fine tuning via autofocus.