Using A7iii with LA-EA5 adapter

[Goronwy22]

I have just bought an A7iii with a LA-EA5 adapter so as to use my old A mount lenses. The camera will not autofocus with two of my lenses, Sigma DS 17-70mmand a Tamron AF 70-200mm. I also get vignetting with the Sigma lens, but not the Tamron, and partly on another lenses, a Sigma EX 10-20mmm. Is this an inherent fault which can be resolved or do I have to buy new E-mount lenses?  

[EMS_MO72]

Hi @ Goronwy22

I do believe that because you're using 3rd party lenses with the camera, some features could not work due to the compatibility.

[det_e_ante]

"* Vignetting will occur if the lens is used with image sensor larger than APS-C size or 35mm SLR, and APS Film SLR cameras..."

Is what Sigma writes about the 17-70mm lens, so I think you're out of luck there. If the wide zoom is APS-C adapted, probably same would apply there on the widest range.

If the lenses are screw-operated, that may also be an issue, as the adapter currently only supports certain screw-motors on a short list of cameras (list is available on the Sony compatibility section for the adapter).