YouTube Video: Zack Arias: Crop or Crap ? I agree with most of what Zack says. However: What annoyed me the most was that he ignored completely the other differences, aside from sensor size. A large format camera is a very different beast in operation from a medium format camera. And while medium and small format are much more alike, the design focus between medium and small format lenses is also substantly different. One cant just act as if all these cameras would do the same in the first place. So for example its quite harder to shoot sports with a medium format camera, instead of a small format camera: less extreme focal lengths possible, lower f-stops, only one autofocus point, possibly limited to low maxium shutter speeds thanks to central shutters. I also would like to point out that theres more differences in quality than just resolution. In general small format uses f1.8 or f1.4 primes and f2.8 or f4 or f4.5-5.6 zooms, while medium format typically starts with f2.8 primes and if there are zooms at all, they are something like f5.6, while the brightest primes for large format are something like f4.5, most are f5.6 and up. Also large format lenses (and some medium format and very few small format lenses) are focused by moving the whole lens - this allows to align the lens elements more precisely. So theres more differences than just sheer resolution between these formats. Yes the differences between APS-C and full frame sensor size ultimately indeed isnt that big. But the differences between APS-C and Full Frame in operation are NOT big. What you can do with APS-C, you can do with Full Frame, and vice versa. The difference is the full frame sensor will have more reserves. I feel that at the price point that Fuji operates, offering fantastic lenses but only an APS-C sensor just seems weird. APS-C sensors are what now ? Well below 100$ or 100€. Full frame is a couple 100 "bucks". Fuji X lenses are fantastic, but they are also not cheap at all. So why use a cheap APS-C sensor for them ? Theres two lenses that make sense to me for Fuji X - the two cheap plastic zooms. The rest is just weird. Why cant I have these lenses for a sensor thats more on the level of the lens price ? Wouldnt make the system much more expensive but would give me a relevant boost in overall quality. Also, for me APS-C (or MFT etc) has NO RELEVANT SIZE ADVANTAGE. Fuji X cameras are simply too damn small for me. I cant hold them well because I have big hands and everywhere I want to put my fingers there seeems to be buttons I'll accidentaly press. Granted the X-T1 looks a bit better than the X-E2 in that respect. But heck even these Sony A7* cameras are still way tiny. I really wouldnt mind the camera creators getting forced to larger mirrorless cameras with a 44x33mm or 48x36mm sensor. Its true if you're looking for more extreme focal lengths and more extensive zoom ranges, APS-C and even more MFT will get big size and weight advantages, but in my mind a mirrorless is something I mostly would want to use with prime lenses of less extreme focal lenghts. So for example if I would get into Fuji X, my lens selection would be right now: 14mm f2.8, 23mm f1.4, 56mm f1.2. There is by the way in my mind absolutely no point to the 0.95 lenses for MFT. A set of f1.9 lenses for full frame would do exactly the same in respect to depth of field, and would only have advantages in every other respect - much simpler construction and much cheaper to produce, higher image quality (all assuming same quality standards), needs to be less stopped down in bright sunlight etc. I also dont agree that the difference between APS-C and Fullframe is irrelevant in practice. Sure a well lit scene can look great with APS-C already. But the reserves in extreme situations are not irrelevant in practice. What I can do with my old D5100 and my current D750 in low light is a huge difference - and having to handle low light isnt a rare condition for me. A big factor why I went full frame was of course also that the Nikon full frame lens selection is worlds better than the half frame lens selection. The lens selection for Fuji X is more expensive, but more complete and of higher image and build quality than the lens selections for Nikon DX and Canon EF-S. Personally I hope that Fujis new system will use the 44x33mm sensor from Sony, will be mirrorless, and will be hand tailored for 44x33mm (instead of many systems right now that are actually 56x42mm aka 645 and only use 44x33mm or 48x36mm as a crop/crippled format. The highlight of the Fuji X system, to me, is still the X100(s|t). Its still the camera that exploits the possibilities of a compact camera the best.