It was a hard choice as to which camera would make my “Camera of the Year 2015” as the amazing Sony A7RII had it in the bag a few weeks ago. Then this SL hit me and surprised me with an amazing overall user experience, which is VERY important when using a camera. It’s the main reason I do not give the Sigma DP series much love here as the user experience is awful with those cameras even though the IQ is incredibly good. I prefer a camera that looks great, is built to a high standard, is easy to use, reliable, fast and has amazing image quality. While the Sony A7RII has all of this, the Leica has a little more, and even though its more than 2X the cost of the Sony, you can really tell this when shooting with it so it’s not just an inflated price for a red dot sticker. [...]
Using M lenses on the SL is a dream as the EVF is mind blowing good and the best EVF made to date, from any manufacturer…and yes, you can quote me on that one. [...]
The SL is in reality, more like a Mini S Type camera. [...] BTW, the Q sensor here has been “tweaked” for the SL.
The fact is that after using the SL I would choose it over the M 240 these days due to the great feel and build, the sensor, the EVF and the joy of using M glass on the camera (Until the next M of course). [...]
This time around the new out of the box Leica is not glitchy nor has my SL frozen or gotten stuck. I have not had to remove the battery for a reset … no issues at all, and the camera as a whole has been stellar in every way. [...]
The new SL is full frame but uses the T mount. The T camera is APS-C but Leica made it with a mount large enough for full frame. Larger than even the M mount. I guess that they had plans all along

For this reason, to use M glass on the SL you need the T to M adapter from Leica. This will send info to the camera when using authentic Leica M lenses. This means the SL will adjust for corrections just like the M does.