Hello everyone, I hope my question is not outside the scope of this page..
I have a Sony Alpha 7 III camera, With the tamron 24-70mm f2.8 lens and the sigma mc-11 adapter, sometimes I see that the focus is not good, I was told that it is better to use Sony lenses, and that this thing has an effect on the lens aperture and shutter speed, is this true?
yes, you are right that has really nothing to do with Stock.
BUT to have a SONY Camera, a TAMRON Lens and a SIGMA Adapter that would for me really give problems. Maybe there is the possibility to adjust the focus afterwards or you might look for an original Sony lens. Hope that helps.
Are you a contributor? I will move this to the contributor forum.
With adaptors, you need to make sure that the combination is supported. I would look for a Sony forum to ask this question. Chances are, that there are more users with that combination of camera, adaptor, and lens.
It would be better to use a lens with a Sony mount, rather than using an adapter. The adapter has an effect on focus, lens aperture (depth of field), and on exposure.
Therefore having a lens directly on the camera is the best thing.
Ultimately, it would be best to use Sony lenses!!
You should watch this: https://youtu.be/goBHCx2kzhs
And yes, it is probably better to get a native lens for your Sony, but it does not necessarily be a Sony lens. Check reviews and may be go testing the lenses at your preferred shop.