So, the year is nearly ended... and I can plan a fresh, new budget for the next year. As I told you in the past, I don't have need of big things. A thing that I'd like to do - even though I've been repeating this for a long time, and did not much so far - is to make more use of primes. In my mirrorless system I only have two: the Samyang 12 mm f/2 (which has been scarcely used, but used a bit, with very pleasant results) and the Sigma 30mm f/2.8 (which has been used only at the very beginning - it was the first lens I bought with the NEX-6 three years ago).
The reason is mainly laziness in unmounting and mounting lenses - also because, curiously, I've seen myself being forced to clean the sensors much more frequently than in the past (I suspect my car - I mostly change lens in the car - has been loaded with lots of dust, because of long drives along white roads). But having the third camera body, it's probably easier to fix my attitude.
So, the doubt is about whether it make sense to replace my Sigma (which was bought because of its excellent performance/price ratio, at the same time wanting to stay cheap because I didn't knew whether the mirrorless switch would have happened or not). There are so many choices... I don't know whether to go with the Sony SEL35F28Z (even though it's a FF I'd take advantage of extra border sharpness with my APS-C cameras) or the Sigma 30mm-F/1.4 C AF DC DN.
Sigma pros: costs half, it's faster (more flexibility, could be used for more than landscape).
Sigma cons: it is really bigger and heavier than the other; it has the stabiliser (I'd like not to have it with a prime lens, because if I go with a prime it means I'm taking my time and I have at least a monopod; furthermore, short focal and relative brightness reduce the need for stabilisation).
Sony pros: it's smaller and lighter; no stabiliser.
Sony cons: expensive.
For sharpness, the Sigma is said to be sharp edge-to-edge even at full aperture, and I suppose the Sony is also very sharp on the APS-C borders.
I lack a comparative evaluation - even with my current Sigma. For this lens, the primary criterium is IQ: sharpness and reduction of aberrations. Buying one of the two candidates I'd really be much better than with my current lens?