I need some help!! I'm trying to fit a 135mm Componon S to my LPL 4500. The spec sheet with the enlarger states that I need a threaded lens plate of 50mm - it is too big for the lens! I measured the thread on the lens and it comes out at about 42mm. I checked the Schneider web page and the current 135mm has a 50mm thread but from the lens date table I think my example is vintage 1975/ 76. Am I missing something! Does the lens need a retaining ring of some description to allow it to fit a 50mm threaded lens plate or does it require the 42mm plate (also available for the LPL). Thanks in advance! Paul