Which means OP's evaluation is wrong because in terms of sharpness the FE35 2.8 has all of them beat.
That contradicts with everything that I've read about these 2 lenses.
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No, this is mostly correct. I shot with the 40 for a good while. The 35/1.7 stays sharper significantly further through the field. Central sharpness is probably better with the 35, but the 40 was okay in that regard. But at 1.4 or even 2.0 it fell apart much more quickly heading out from center. The 40 almost had too much contrast. The 35 has boat loads as well but it's a bit gentler. Never noticed the yellow cast but that's fixable. The 35 also has significantly better bokeh. The 40 has strong outlining at 1.4, doesn't get smooth until 2.8.
I have one, and used it a lot on my 5DII. It was one of my favourite lenses at the time, since its performance was really good to me (without any appropriate testing though, so maybe I just was biased because I liked this lens' form factor) and the pancake size was ideal with this body: it was just short enough to not protrude further than the body handle. I haven't used it since I moved to Sony though. Not saying it wouldn't be worth it, but I immediately started to use my M lenses when I got my A7II, and the 35 F/1.4 was more attractive than the 40 F/2.8 due to its aperture and shorter adapter ring.
Interesting. I have both the Loxia 35 and the Ultron 35/1.7 for use on an A7ii, and my conclusion is that the Ultron is definitely better optically at all apertures. As I mentioned in my prior post 5 months ago, it suffers from significant vignetting and color shifts on Sony cameras due to the thick sensor cover. Fortunately, this is easy to fix in post. Lightroom users can download the Adobe Flat Field Correction plugin, and users of other raw converters can download CornerFix. Both remove vignetting and color shifts very readily. Since I discovered CornerFix, the beautiful CV Ultron has become my 35mm lens of choice.
