Sigma has introduced a new service that will help anyone who has recently converted to a Canon from a Nikon camera, or vice versa (or to and from Sony, Sigma and Pentax systems, if anyone does that).
The service will enable you to convert the Sigma lenses that you currently own to a different mount for your new camera, rather than having to replace them.
At the moment, the service will only be available for lenses from Sigma's three new product lines - Art, Contemporary and Sports. The service will cost you money, with Sigma changing the parts for the relevant mount and its internal core system.
Currently, the following DSLR lenses are eligible for conversion: the 35mm f/1.4, 120-300mm f/2.8, 30mm f/1.4, 17-70mm f/2.8-4 and 18-35mm f/1.8. Conversions are available for Sigma, Sony, Nikon, Pentax and Canon mounts.
The service will also be available for switching between Micro Four Thirds and Sony E mounts for compact system cameras. So, you can change the 19mm f/2.8, 30mm f/2.8 or 60mm f/2.8 between the two systems.
It's not possible to convert a lens to a mount that Sigma hasn't released, while some specifications, such as optical stabilisation functions, will be subject to adjustment after converting the mount.
Sigma is yet to release any pricing details for this service, but it should be significantly cheaper than replacing a lens entirely. The service will be available from September.
Watch this space for more details as they become available.