Steinheil Munchen Unofokal 15cm f4.5

Can anyone tell me anything about this lens. I couldn't find any reference to it through Google. It seems to have a big image circle, at least 4x5. The rear element actually seems to be two. I shook it while I was cleaning it and it rattled - I thought it was broken but there seems to be two elements threaded together - I couldn't get enough grip to separate them but I was able to turn it down so it isn't rattling anymore.

You can get a sense of scale by seeing it on the lensboard of my 4x5 Anny. I didn't measure the thread of the mounting ring, but it's a bit bigger than 39mm (maybe 42 or so)

The shutter, missing mode dial aside, seems to work surprisingly well - I used a little screwdriver to switch it from Z to settable speed mode and they all seem pretty good - interestingly, when I turned past 1/200 towards 1, the mode select went back to Z, maybe a built in method of protecting the spring. Anyone know if there's a way to get another dial?

Thanks,
Dan

The VM says "This was the "new" anastigmat in the 1906 adverts. and it was a good one. It was a dialyt, but one with all the glasses of about the same focus- more interesting perhaps was that the inner glasses become more close together than was usual in this type"

The name is also spelled Unofocal. The lens was made under license as Unofocal by Beck (London).

Yours was made in 1945, or possibly January of 1946.

As Dan said it's a kind of Dialyte. It got the name from the special construction with all four elements having the same focal length - two positive, and two negative. That didn't last long though, since it was quicly found that using slightly different focal lengths made a better lens. But the name stuck.