"Bought this EF to L-mount adapter to go with a new Panasonic Lumix S5ii. As a Canon user being able to utilise my existing lens investment was important. Although Sigma only really claim it will autofocus properly with their own Sigma EF lenses it does a pretty good job with most Canon lenses, certainly good enough to be able to use the S5ii as an alternative body on my Canon lenses on big trips. Until the Lumix S5ii was released the previous models only supported single (not continuous) AF but the S5ii cameras now support continuous AF through the Sigma adaptor. All my main Canon lenses such as 70-200mm f2.8 L IS II and the 70-200mm f4 L IS work quite well - slower than native on a Canon 5 series body of course but quite useable. They do occasionally get stuck at minimum focus, but its rare. In one shot focus it tends to slightly run past then returns and locks accurate focus, continuous focus is pretty good and I prefer this mode. There is minimal hunting and once it gets lock its very accurate. The 100mm L IS macro focusses fine, as do the 28 f2.8 IS and 35mm f2 IS lenses. The only Canon lens I have which is slightly problematic is my 24-70mm f4 L IS which focuses but is very jerky. I also tested my Samyang AF 14mm EF mount lens - this focuses fine on the Lumix through the Sigma adaptor. Given the speed of focusing I wouldn't use a Canon lens through the adaptor for subjects such as sport. motor racing, your dog at speed or birds in flight. But for circumstances where you need accurate autofocus as opposed to speed its a very workable compromise. So in summary it works pretty well, gives continuous AF on the S5ii camera and allows me to to use my Canon investment on lenses on the new Panasonic Lumix S5ii camera. It can be a little slow and is not ideal for fast focusing situations but the focus is very accurate. Recommended as an interim solution if you are considering transitioning from Canon to Lumix."