Yes—using a smart EF-to-Sony E adapter, many Canon EF lenses and at least some Tamron EF-mount lenses can retain electronic functions on the Sony A7R. Based on the reports here, autofocus can work, and aperture control, stabilization (IS/VC), and EXIF reporting generally work as well.

The main limitation is autofocus performance: it tends to be much slower and can be unreliable compared with using the lenses on a Canon DSLR or using native Sony lenses. So while the setup can “work,” it’s not ideal for situations that need quick, dependable AF.

For your stated uses—landscape and studio—it should be a reasonable solution, especially since the A7 series makes manual focus easier with tools like focus magnification and peaking. If you were shooting events or sports, adapted Canon lenses would be much less suitable and would require more practice and compromise.

In short: electronic compatibility is possible with the right smart adapter, but expect good support for aperture/IS/EXIF and only limited AF performance.