The 35mm Loxia (Image courtesy: Stockografie).
Stockografie (Click here) tested both Zeiss Loxia lenses:
The Zeiss Loxia 2/35 as well as the Zeiss Loxia 2/50 is a wonderfully crafted lenses. They are built to withstand almost anything a photographer could run into. I would not hesitate to use these lenses under harsh conditions such as rain, dust or any other kind of influences.
If I would have to choose between one of the two I would go for the Zeiss Loxia 2/35 but that is only my personal preference as I like the 35mm field of view better than that of the Zeiss Loxia 2/50. In terms of image quality both lenses are amongst the best you can get for your A7 series camera with a native E-Mount.
The Loxias are in Stock in:
50mm in Europe at Photo Porst eBay (Click here) and Photo Petzold eBay (Click here).
35mm in Europe at Photo Porst eBay (Click here) and Photo Petzold eBay (Click here).
50mm in USA at PoppFlash eBay (Click here).
50mm in Asia/Australia at DigitalRev (Click here).