YYV_146
Well-known
You'd better stem your enthusiasm a bit? Only few M lenses of 50mm and below will work on A7 without smearing and tinting the corners. Your CV 35 1.2 will work well, but your 50 Sonnar is one that won't. R and other retrofocus lenses work better than M in the mid-wide and normal focal lengths. This was the initial confusion: folks thought the A7/r was a new low cost, high ISO platform for M lenses, but they turned out instead to be the digital bodies that saved R glass.
Isn't the 50 Sonnar just incredibly soft in the corners to begin with? The very design of the lens was to provide a "classic" rendering with aspherical elements or excessive correction.
For what it's worth, the similar 50lux pre-a does not show outstanding corner issues. Neither does any of the other Leica 50s I've tested.