Sharpeness comparison
Here the images show a 100% crop in of the in-focus areas only; corner sharpness will not be treated.
A1) 1/250s @ f/5.6 | Rollei-HFT Planar 50mm f/1.8 - 100% crop
A2) 1/250s @ f/5.6 | Carl Zeiss Jena Pancolar MC 50mm f/1.8 - 100% crop
B1) 1/125s @ f/8 | Rollei-HFT Planar 50mm f/1.8 - 100% crop
B2) 1/125s @ f/8 | Carl Zeiss Jena Pancolar MC 50mm f/1.8 - 100% crop
C1) 1/60s @ f/11 | Rollei-HFT Planar 50mm f/1.8 - 100% crop
C2) 1/60s @ f/11 | Carl Zeiss Jena Pancolar MC 50mm f/1.8 - 100% crop
D1) 1/250s @ f/4 | Rollei-HFT Planar 50mm f/1.8 - 100% crop
D2) 1/250s @ f/4 | Carl Zeiss Jena Pancolar MC 50mm f/1.8 - 100% crop
E1) 1/250s @ f/1.8 (lens hood used) | Rollei-HFT Planar 50mm f/1.8 - 100% crop
E2) 1/250s @ f/1.8 (lens hood used) | Carl Zeiss Jena Pancolar MC 50mm f/1.8 - 100% crop
F1) 1/60s @ f/4 | Rollei-HFT Planar 50mm f/1.8 - 100% crop
F2) 1/60s @ f/4 | Carl Zeiss Jena Pancolar MC 50mm f/1.8 - 100% crop
H1) 1/125s @ f/2.8 | Rollei-HFT Planar 50mm f/1.8 - 100% crop
H2) 1/125s @ f/2.8 | Carl Zeiss Jena Pancolar MC 50mm f/1.8 - 100% crop
(I did not focus exactly the same in some images, one is also a bit blurred and I am very sorry)
My very modest opinion
For me, it seems that, when in focus, at aperture of f/2.8 - f/4 or larger, Pancolar is a little bit better; from f/4 - f/5.6 to smaller apertures, I prefer Planar, with its micro-contrast, which is clearly superior.
However I will not prefere one above the other for the sharpness, because I know they are very very sharp lenses, but I will choise and exchange them only for the tone and look, the main things at which this confrontation was aimed.
Thank you all for the comments and please, leave your sincere opinions.