Sony a7r and adaptors

I'm planing to switch to sony from Nikon. I'm pretty much selling everything except my beloved zeiss apo 135mm f2. My question here is. If I buy an adaptor and mounted into the upcoming sony a7riii. With there be any focal change because the adapters arendistant from the sensor. And will in body image stabilizer work along with focus peaking in the view finder?

In general, and especially with upmarket optics, you lose a lot in trying to "adapt" a lens with one camera mount to another camera mount. That applies especially if there's an optical element in the adaptor. Even without the optical element, you will find restricted usage, with not all facilities available.

Bite the bullet, sell the Nikon mount lens, buy the equivalent in the Sony mount.

Have a read here:
http://briansmith.com/nikon-lens-adapters-sony-e-mount-cameras/
Sony E-mount seems quite easy to adapt, but as mentioned by John P you are likely to lose some lens functions. But I can understand why you wanna keep it.

The A7Riii is a full frame camera. It's much thinner than Nikon bodies too. Because it's thinner, if you were to just mount the Nikon-mount lens onto it without an adapter, then the focal point would be off. The reason you can fit different lenses onto the mirrorless camera is because the mount adapter makes up for the difference in distance between lens mount and the sensor. So no, you will not have any cropping of the image circle and therefore your crop factor will be 1x.

I believe that since the A7Riii uses IBIS, that your stabilization will work regardless of lens used.

It won't be a problem, everything will be working fine. If your nikon was a fullframe, focal length will be the same. Ibis will work and focus peaking and magnifier will be fine. If you like manual lenses but want to have af feature, you can look techart autofocus adapter for leica m mount lenses.

But if you have this, and get nikon f to leica m adapter, put it together, you will have autofocus on your beloved lens.

Ok

Avoid lens adapters.

https://www.diyphotography.net/three-adapter-options-use-nikon-lenses-sony-mirrorless-nikon-f-sony-e/

Similar adapters can match, don't worry.