Thank you all for valuable comments!
To me this lens is as slow as Color Skopar LTM and M versions I used for few years.
Summarit 35 2.5 isn't small lens at all after Skopars. It is also very different for how focus ring feels. Summarit is Leica.
Focus tab is just few mm less wide what I want it to be.
And lens ergonomics are done for focusing, framing with RF/VF , not for scale focusing and framing from the waist level. Close proximity of focusing ring and aperture ring should works very well with exposure adjustments by indicator in VF, I guess.
Summaron is different in rendering, white and slower (insignificantly).
For indoors @1600 I could use lens up to f4. But with f2.5 I'm off the dark streets.
All of the pictures I provided above and few more here where taken at maximum aperture. It isn't clinically sharp, but present, OOF areas rendering is pleasing.
At minimal focus distance, I was focusing on "f" letter.
And following are examples how I prefer take pictures of people I know. Not sitting portraits, but something real, the Moments.
Cheers, Ko.