I know this is an old thread, but would like to ask the forum a question.

A friend kindly gave me a beautiful Nikor 150mm enlarging lens, and I'd like to use it to enlarge 5x5 negatives created using my 5x7 camera.

The trick is that the lens has a thread that's larger than 39mm, and I haven't been able to find information on what the thread size might be.

My questions are:
1. What size thread might this lens be?
2. Do I need to worry about my Omega D2/Pro-Lab4x5 and bellows draw being long enough?

When I get home today I'll post a picture of the lens. Perhaps that will give more clues.

Thankful for your help!