Leica M Mount 6-Bit Encoder kit (includes pens, encoder, instructions and table of codes). The coder clips on to un-encoded lenses and allows quick and easy coding of any (not limited to) M/LM, ZM and VM mount lens. 

Once the lens is encoded, your Leica M and SL2/SL3 camera will know which focal length lens it has mounted and record that information in to your photos (meta data) which will then be displayed in Lightroom and any other software allowing you to filter your photos by lens and focal length.

Your Leica will also apply various adjustments including vignetting, chromatic aberration and barrel distortion for cleaner JPG images and less post processing for RAW files.

An added benefit for SL2 and SL3 users when used with the Leica M adapter, is setting the correct image stabilisation for the lens length.

Any other manufacturer lens can be coded to the closest Leica equivalent, generally improving the quality of your photos through the automatic corrections applied and the recording of meta data for lens length (28mm, 50mm etc).

For coding third party lenses, some experimentation may be required to find the closest and best match but all M mount lenses can be coded.

The kit includes a compatible white and black pen, along with the 6-bit coder, instructions, and table of lenses and what to code them to. 

If you have a lens not listed in the table below, mounting your camera on a tripod and photographing a scene uncoded, then photographing the same scene with a few of the closest codes will allow you to compare and choose the best one for your particular setup. This should only take around 20 minutes for more than one lens due to it only taking around 20 seconds or so to clean a previous code off a lens and then re-coding it.

A few lenses can have a screw where a 1-bit should be, filling this in with white allows you to then either leave it as white or place a black mark on top of it for successful coding.

Note: The QR code on the encoder takes you to the instructions online which includes the table of lens codes. If you are out and about with the encoder and pen in your bag, this should hopefully help code your lens quickly.