Zeiss Protar F=29cm

[baachitraka]

I have no idea about this lens. Is it some sort of rare and how good are they for portraits?

 

[Vaidotas]

Protars were made in various layouts, if you are talking about Protar VIi single cell, it has ~ f/12 opening, a bit challenging for portraiture.

 

[Ron (Netherlands)]

highly priced, that's for sure; the double protars are real collector items. In fact you get 3 focal lengths since you can use the cells separate or together.