My experience with the original FA35/2 is similar to yours, amstel78. I had 2 (actually I think 3) copies of this lens. My first one was a new Samsung version; then I tried one or two used Pentax FA35/2 copies, hoping to get a different result.
I kept trying, but I decided the lens wasn't for me. Simply put, the image quality suffered noticeably at apertures wider than f/2.5. Softness was part of it; the other was probably the "glow" that you describe (I don't have a better description either). But the image degradation (perhaps a lack of contrast?) at f/2.2 was obvious and consistent on all my copies. It's clearly in the design of the lens - and I didn't like it.
While you may be "spoiled" by the D FA * 50/1.4, I don't think it's tainting your view. Your observations still appear accurate and valid.
Of course it still produces nice images, and this includes yours. In fact I rather like the DA35/2.4 variant, but it's easy to like a lens that performs so well wide-open while being so affordable. It produces bokeh circles with high IQ. But I understand it's not good for FF.
So you can use this somewhat overpriced (IMO) (HD)"FA35/
2.5," or wrestle with the amazing but hard to tame FA31/1.8 that's fantastic wide open and can't seem to produce harsh backgrounds no matter what you do. But it also was difficult for me to get many interesting images out of it - at least on APS-C (I never tried it on FF).
Last edited by DSims; 04-07-2019 at 08:43 PM.