I have the 18 SEM, 35 FLE and the 75 cron. I really like this combo a lot, in terms of the spacing between FL. I started with the 50 lux but it's become the red headed step child of my M lenses. One of my local leica dealers has a German made 75 lux that I've been thinking about trading my 50 lux and 75 cron for, but I'd have to CLA and code the 75 lux. There's a lot of sentimental value with the 50, makes it hard to trade even though it doesn't get used that much any more.