This adapter is made well, and Single-AF works well with my Olympus E-M1 II when mounting a Canon EF-S 55-250 or the Tamron 18-400. Autofocus is quicker on the 55-250. Continuous-AF is not rated to work, although the E-M1 II doesn’t seem to mind. Either way, this is really for reusing Canon lenses for casual shooting and slow/still subjects. Autofocus is not fast enough for action.The Viltrox EF-M1 adapter, unlike the Commlite AEF-MFT, seems to require one shot to be taken before lens IS activates. (The Viltrox EF-M2 II also seems to have this issue.) My workaround is to let my camera go to sleep rather than turn it off.Another advantage of this adapter is that it includes a micro-USB port for firmware upgrades. (I actually got the Viltrox EF-M1 after an upgrade to the Tamron 18-400 firmware “Version2” made the Commlite stop working with that lens.) If you decide to upgrade the firmware on this Viltrox EF-M1 adapter, beware that a Windows PC is required. I tried multiple times upgrading and downgrading with Macs, both Intel and Apple Silicon, and none of them worked. When I borrowed a new Windows PC, upgrading worked on the first try.For less than US$150, this is a good alternative to the similar adapter by Metabones. The difference is that Metabones seems to have many more resources devoted to certifying functionality with a larger collection of Canon lenses.