Found this Font in an old german songbook.         
Even though its old, the Font was just applied in a newer version from 1980 to today. The current version is from 2015.

The Font is very easy to read even in low pt (i dont know it exactly, but a capital "T" is 2mm in height). The "5" and "7" look very untypical to me (as seen in the first image "1857"). The first image is in full italic, but the same font. The Book itself is just DIN A6 but even from far away the font is very easy to read - which is impressive and exactly what i need.

Anyone has any clue? Otherwise im okay with similar "easy to read in low pt"-Fonts.
Best regards       
Envoy

Walbaum Antiqua in the original version: https://www.myfonts.com/fonts/linotype/walbaum/

I usually recommend the Stormtype version though. It’s “10” versions are even better for smaller text:
https://www.myfonts.com/fonts/storm/walbaum-10-pro/