Hi guys.
Just wanted to report some positive news for once, as it's usually only bad service that gets posted.
I had issues with my Sigma 1.4x tele-converter. I noticed 3 out of the 5 screws in the mount were missing, which was giving me a bad connection between lens and body and reporting F0.0 in the camera display.
I dropped an email To Sigma Service UK, promptly had a reply, and now have some new screws on their way to me free of charge.
10/10 for Sigma Service


