Quote Originally Posted by tony lockerbie View Post
Hi, looking for a good quality 150mm enlarging lens, must have a 39mm screw mount (to fit a Durst lens board) Interested in Rodagon, Componon S or El-Nikkor.
I may be wrong, but according to my Beseler 45 MXT enlarger instruction manual, both the Rodagon and Componon-S 150 mm lenses are 50 mm thread. At least they require a Beseler 50 mm flat lens board. Even the Componon-S 135/5.6 is 50 mm. The El-Nikkor 150 mm is also 50 mm screw mount, but there is a 39 mm adapter.

To fit an M39 screw mount, you will need a Rodagon 135/5.6. Don't know about the Durst enlarger, but my Rodagon 135/5.6 requires an extended lens board when used on my Beseler 45S.

Bottom line is that I doubt you will find a Rodagon, Componon S, or El-Nikkor 150 mm enlarger lens with an M39 screw mount. You may have to go to a 135 mm focal length. Even then, you should check whether your enlarger will work with it on a standard Durst lens board. Before you decide, you might want to read Chapter 6 "Enlarging Issues" in Post Exposure: Advanced Techniques for the Photographic Printer (2nd Edition) by Ctein. It's available free online. He evaluated all sorts of enlarging lenses including 4x5.