Hi,

I bought an used EF-Adapter for my XL1s but there
was no user-manual in the package.
Can anybody help me out or tell me what
function the button on the left side has (also the
lock-function).

Thanks for help
Jochen

The top button is the release lever for the lens. The lock button locks the AE functions of the XL1.

The following link will lay it out in better detail (scroll down for english):

www.canondv.com/downloads/accessory_manuals/ xl_ef_adapter.pdf