The 645D is a really great camera, but in common with all medium format cameras has very basic autofocus - indeed most modern m4/3 cameras would beat it in tha

The 645D is a really great camera, but in common with all medium format cameras has very basic autofocus - indeed most modern m4/3 cameras would beat it in that regard. High speed autofocus is not why you buy a medium format camera! I love medium format - I'm quite seriously eyeing up the new hasselblad X1D - but in my view they are strictly for static subjects only - landscapes and portraits (plus other things like product and architectural that are pretty specialist and outside my area of expertise). I think in many ways we might actually be in agreement, albeit from slightly different perspectives. Two notes though: 1) Weight is actually an asset for stability, assuming your support system is sorted properly (by which I mean a rock-solid tripod with a proper wimberley head). The weight dampens vibrations, and the support system means that it's perfectly balanced, and can smoothly track moving objects, even at speed (which helps the autofocus a great deal). I don't know anyone who'd attempt to handhold a D5 with an 500mm f4 lens - that's just not going to work :) 2) DxO scores aren't something I get overly excited by. The important things about a shot are firstly the composition, which has nothing to do with the sensor at all, and after that comes making sure that the things that are supposed to be in focus are critically sharp, which comes down to focus (and good glass) - but that's difficult to assign a numerical score to so DxO doesn't do that. Instead they obsess over incredibly minor differences in colour rendition (which after it's been through the awful adobe raw converter won't matter anyway), performance at ISO levels way too high to actually use, and differences in dynamic range way above what any printer can reproduce. Not that useful, at least to me. The availability is indeed a valid point, and is basically why I'd buy this product should it turn out to do what it says it'll do. Having said that, I carry a heavy camera bag around with me a lot of the time, and for me that's a tradeoff I'm happy to make for the flexibility of being able to take lots of different kinds of shots when I'm out. That's really what I meant by this whole thread - the product mentioned will be fantastic for capturing some landscapes when I don't have the option of a full camera bag, but it's never going to be able to replace the camera bag. Which is why it's (for me) a DSLR addition, not a replacement. EDIT: Forgot to mention - I 100% agree about the image quality, and that's what I meant when I said lots of amazing shots are taken by people with very similar levels of equipment. The high end pro bodies tend not to give you that much more image quality (some of them give you more resolution, but again, that's something that gets overhyped, and isn't always needed) - they give you more controls, more durability, more buffer and so on, but with the right talent, technique (and glass) you can take a NatGeo worthy image on a $500 camera, no problem.