The Sony (and most mirrorless) don't track focus well and if your adapting full frame lenses, like Canon, Nikon, Leica, then it's just hit and miss in regards to the adapter and the lens.
To really make any of the Sony A7 cameras work well you need either the new Sony FE lenses or adapt the Sony's larger A series lenses with their smart adapter.
Which leads you to the bottom line of a new lens set along with a new camera. If size is that important then it might be worth it (as long as your subjects are still).
It depends on how much you want to give up for size. Track focusing, high battery use, new lens set.
It seems the people most enamored by the A7 series buy the R and use it with canon tilt shift lenses, but then again their subjects aren't moving and they're not shooting walk around imagery.
Lately most of the A7 series have had price reductions. Don't know what this means, but usually it is because there is a new version coming on line. This may or may not matter to you.
Honestly they're cheap to rent from borrowlens and those other online rental companies, so before you dive deep, why not just rent for a week or so and see if that works?
IMO
BC
I have access to my own wide angle Canon Glass, I also have access to some old Nikon Glass and some old Leica Lenses. I am looking at the Sony A7 or A7r soon and wondering which lens adapter might be best to try first. I was thinking to try out the Leica lenses with it, but at the same time wondering what is the best Lens adapter; Metabones ? What focal length works best with all of the adapters that are out there?
I have both a Canon 5d MKII and a 1Ds MKIII both are just getting too heavy with normal everyday use that is not a paying job; (i.e; for my self, heck I just don't want to pick them up and I'm not a small person).
Is it worth getting one of these Sony's? There does seam to be lots good said about them and I have read some bad also (shutter vibration in a certain range; 1/30 to about 1/125th) I mostly use a tripod for my landscape work so I don't think that will be an issue.
Love to hear the good and the bad ...