The classic Leica M view finder camera with the integrated split image range finder was long time the best you could get for the FX format. With the introduction of reflex cameras this was challenged outside the 28-90 (135mm) mm focus length. Also macro photography became much easier. Latest developments show a trend to mirror less live view screen or electronic view finder cameras. Fuji combined all together with an optical / electronic view finder and a live view screen. To keep it small most of this products use APS-C sensors (crop factor 1.5). Depending from preferences and seriousness it can make sense. To exploit the FX format to its full extent still the classic M view finder or the reflex camera are the right equipment. FX format is very focus sensitive to point and depth. Correctly applied this opens a wide field of creativity. Digital range finders or screens don't give a similar level of feedback to date. The view finder concept allows to build a FX camera body with small dimensions. Lenses can be designed to close sensor distance what makes them small and light too. With its discrete appearance and low shutter noise (M9 could be better) it's a companion where ever you go.