I tried the first M-mount adapter on the market for tech art and really enjoyed it, which you can read here. The Pronto adapter came out later and is probably based on software licensed from tech art and now there is a Proton Mark II, which seems to be a slight update that you can read about below:
The PRONTO Leica M-Mount Lens to Sony E-Mount Camera Autofocus Adapter from FotodioX allows traditional, manual-focus Leica M-mount lenses to function as autofocus lenses on select Sony E-Mount mirrorless cameras. By utilizing the camera’s phase detection autofocus (PDAF) system, this adapter’s helical focusing mechanism physically shifts the lens position up to 5mm on the Z axis, enabling autofocus even on manual-focus lenses. It supports both AF-S and AF-C focusing, in addition to face-detect autofocus and 5-axis image stabilization on enabled cameras. An integrated function button allows the user to enter various focus modes as well as setting the focal length and maximum aperture of the lens used on the adapter for optimum compatibility. Also, by utilizing separately available lens adapters with a Leica M-mount, various other lenses may achieve AF with this adapter.
When the lens is set to its close-focus position, the adapter’s extension can be used to achieve macro capabilities, or set the lens to the infinity focus position to enable autofocus within its entire focusing range. Performance is optimal with 50mm lenses and wider, telephoto lenses may require coarse lens focusing before using the adapter for fine tuning via autofocus. This adapter is designed to support lenses weighing up to 1.3 lb.
Compatible Sony Phase Detect AF Cameras
Compatible Sony Hybrid AF Cameras
Pronto Mark II: B&H Photo