Looking for information about Busch glaukar 307mm/f9

[tbw777]

Purchased a rare lens Busch glaukar 307mm/f9, presumably it's a triplet. Have searched the internet but can't find any information. I have a glaukar 140mm/f3.1 but it is from a different line.
Does anyone know what this is?
What do the numbers 1 and 2 on the ring mean?

 

[Vaidotas]

It’s a slow triplet supposingly for technical applications - repro work.
Here is another one in similar focal lenght but a bit faster - f/7.5 with serial 353132.
Weirdly enough mine has only four f stop positions.
Have no clue what 12 marking means on your specimen.

 

[tbw777]

Wow, interesting, but 300mm instead of 307mm
Can it be used for portraits or not? I have a range of iso values: 1-200.

 

[Vaidotas]

It’s not THAT venerable fast Glaukar, but sure you can use it for portraiture, desirably on 4x5 or smaller formats.

 

[tbw777]

4x5" is the maximum?

 

[Vaidotas]

Consider this lens as Cooke series V (f/8) substitute with similar coverage. That might be 8x10 inch with generous movements.

 

[tbw777]

Thank You for answer, im return later with samples