Which would you rather purchase and carry around a race track for 6 hours: a FF camera with a 400 f/2.8 lens or an APS-C body with a 300 f/2.8 lens? How about trying to capture a skittish tiny bird from too great a distance, when you really need a 1200mm lens? The phrase is "focal length limited". You may have high hopes for the M-system. I certainly did at one point, but there don't seem to be enough of us to get Canon's attention. Incidentally, an M5 looks ridiculous on my Sigma 150-600 Sport zoom but it works remarkably well.Can someone help me understand the advantage of having a large RF mount for an APS-C sensor? Mounting a high end expensive RF lens on an APS-C sensor camera makes no sense to me. Many people like Fuji X mount cameras because they are compact and overall system cost, weight and size are reduced significantly. Personally I hope Canon would revitalize the M series and develop some high quality prime or zoom lenses for travel photographers, and concentrate on producing more affordable RF bodies and lenses.