Sigma 150-600mm not Autofocusing on Canon 70D

[josap]

Hello! Just recently my Sigma 150-600mm contemporary lens is not auto focusing on my Canon 70D. I called Sigma and it seems like I will need to return it for repairs. Does anyone here have any tips or tricks that might be able to get it working? Is there something simple I am missing? Thanks for any help!

[jrhoffman75]

If it used to auto focus and now doesn't check the AF-MF switch position. Do other lenses AF properly with the camera? If those checks work OK then I would believe Sigma; I can't think of anything else to check.

[ebiggs1]

I have six or seven super zooms lenses and I do find that sometimes AF is finicky. This seems to be true on any and all models. It does not happen often so my question is does it focus at all or does it never focus and perhaps doesn't even try? If it never tries to AF it is broken and has to go back to Sigma. 

If it does try to AF that's a different story so come back for it.

[Waddizzle]

Do you use back button focus?

if it doesn’t work in automatic setting on mode dial ,  but it does focus with other lenses, your Sigma needs service.