Enna Munchen Ennalyt 4/24 Exakta mount

[Volunteer]

Hi all.
I got ahold of this lens and am very confused. I have no previous experience with Exakta lenses, but the other two I acquired look 'normal'. While this one...
First thing I noticed is that the aperture ring has 2.8 and 1.9 aperture values written. And the lens is f4. I'd guess it's some kind of lens with an interchangeable mount.
The whole bottom half can be removed with a simple twist (I forgot to photograph that). I just removed the bottom plate to see why
I can't close the aperture.
The focusing seems smooth (but can't really tell cause the camera is faulty).
Do you know anything about it?












Bottom plate removed.

[calvin83]

Your lens belongs to second version of the Enna Sockel mount.

http://captjack.exaktaphile.com/Enna%20page.htm

http://photobutmore.de/exakta/objektive/ennasockel/

[Volunteer]

Wow, thanks. This explains everything.