I've been having a debate as a new user of the A7ii, as to which lenses to buy, I have had some experience of the most popular Sony E mount glass (24-70, 55, 35/2.8) having tried an A7 last year but the A7ii feels a much nicer camera, I'm coming over from a Nikon D750 as I've been a bit fed up lugging huge lenses around all the time and rather than split systems (for example keep my Nikon and add a Fuji CSC) I feel that the A7ii can give me the best of both worlds, great FF IQ and a body that can be larger when I need (Battery grip), or smaller when I'm travelling or sticking the camera in my everyday bag.
I'm finding lens choice complicated a little by the fact that the 24-70 f4 isn't great, normally I'd have that as my staple lens and then a wider prime but the poor 24-70 makes me wonder if I'd prefer the 16-35 and the supplement that with primes further up the line.
My initial plan for this year (and partly why I bought the A7ii) was to "simplify" my photography a little and allow me to refocus on the image, the shot rather than what has been for the last year an almost constantly evolving kit bag (D800>XT1>D750>D810>D750).
To that end I've been thinking about the 3x Loxia lenses, (21,35 & 50) as that would cover off the vast majority of my shooting and I love the idea of manual focus, most of what I do is tripod based anyway so the speed of AF isn't needed.
However the Loxia 35 (which I've tried) seemed "ok" rather than spectacular for £900 worth so I may forgo that for the 35/f2.8 and save some cash!
I bought the Metabones EF Adaptor with it and used a friends Canon 17-40L with some success but I feel this is getting away from one of my main goals of buying the A7ii, simplification and downsizing!! so I suspect I will pass on the Canon glass and sell on the Metabones.
I had a look through my images over the last 12 months and tried to figure out what focal lengths I actually use and discovered that I don't do a lot of shooting wider than 24mm, now thats probably partly because I haven't always had a wider angle but even then anything "wider" has tended to be 18-20 so I think the 21mm would probably do me fine, its only a step back!!
That also pointed to around 35 and 50-60 being key focal lengths for me, which leads me to the Loxia or Zeiss 35 and the Loxia or Zeiss 50/55.... too many decisions!