I was asked by a member to weigh in here if I could add my take on these two lenses. I had the 35 and 50 with my A7r . I also had the 35 2.8 and 55 when I first started with the A7r previous to the Loxia. I'll start with the 35 2.8 and I just had bad corners with my copy even at 5.6 it just did not look good. I also had the 55 which I tested against the Zeiss 135 F2 and the Sony Zeiss 84 1.4 ZA lenses . I ran a big test between the 3 and long story short the 55 was brillant against them with the 135 taking a slight edge over the 55 that folks is outstanding performance and the 85 ran in third. My only criticism of the 55 was just a bit clinical in look. But in the end at some point I needed something else and sold it, dumb move considering I just rebought it this week. Lol
Anyway let's move on to the the Loxia 35 which I really liked the Zeiss look of it and I love how both of these lenses preform in regards to use and focus. I tested both of these lenses pretty hard and I found at F2 the 35 had some coma but still pretty sharp wide open but the one thing all along was I wanted the 35 1.4 more. What made me sell the 35 Loxia was when I got a good run with it in NY shooting the city, I was not really thrilled with the bokeh of it and the 50 was so much smoother looking. Now the 50 is a different story as wide open its very sharp the corners are very nice and had really nice bokeh. But more importantly they both have nice character to them there small and the best OEM hoods around. I never use OEM lens hoods and always replace them with metal screw ins. But these Loxia lenses have great hoods.
Now I should point out because I do buy and sell lenses a lot but no one should take those actions as a negative. I mostly do that because I want something else. Honestly there's not many lenses that are something I would call out of my dead cold hands. I am very neutral to gear , I need something I'll figure out a way to get it and sell whatever I need too. So please never take those habits as a negative because I do get email like why did you sell that you loved it. Well I married one person that's enough being married too. lol
Now I really like the Loxia 50 as there is nothing bad about it , it has great sharpness and a great look to it with very nice rendering and it's really hard to have anything bad to say. The 35 F2 is also very good and the coma is there but stopping to 2.8 it pretty much goes away and some may like the bokeh on it. I just found the 50 a very sweet lens which brings me to my latest decision last week between the 55 and 50. Honestly a really tough choice but in the end the deciding factor just came down to AF. For some work I just need AF and if this was not my Profession I would be more just manual as there would be that freedom. But a working shooter you try to avoid the risks of blowing things when the heat gets turned up on some gigs where time is of the essence so you lean more to AF glass and the 55 is very good at it and with Eye AF being so good it's hard not to use it as often as you can. So the 55 right now makes sense.
Seriously if I was not a working Pro these comments would be slightly different because I would lean more to manual focus lenses because that has been a very large part of my career. But I'm not a spring chicken anymore either. So I like having the AF option and I'm also very much into trying to stay native to make use of all these AF abilities. I know I jumped off the Loxia lenses but I think it's important to understand the logic you have to think about when deciding these things.
Honestly I get a lot of emails and PMs a lot of them with folks looking for help. I even get other Pros and why I go through these kinds on open conversations because I think they help folks think better and on a more logical level and figure out what may work for them.
But in all honesty the Loxia 50 is just a very nice smooth looking lens. I'm hoping they just keep coming with them but I also think they need to redesign them like they did with the 21 coming. We are in anew era with very large demanding sensors and we have to refresh.