I just found a 50 1.8 takumar M42 (single coated) and 2x teleconverter in amongst some negatives from a few years ago. I'm wondering if I should spend the $40 and buy an adapter. The reason this is a tough decision is that I already have two 50mm's already, a Jupiter 8 and industar 61. So how good is the tak 50 f 1.8? I use my 50's to stitch quite often, and any improvement is great. Also I have no telephoto lenses longer than 50, are there any good M42 60, 85/90 (fast), or 180's? Any insight is appreciated. Thanks, John.