All above - Canon 5Ds.
All above - Nikon D750.
Superb image quality, great handling, extensive lens systems, robust build quality. The things that Nikon and Canon owners take for granted.
But there is a mirrorless alternative around these days, Sony FE. Full-Frame, 42.5MP at it's best and 4K video. And Sony have just announced three new lenses.
But for me Sony still can't get this right. And it's because of their decisions. They obviously rushed into the E system, which was obvious from the release of two cameras but only one lens at the start. So a system from scratch takes a while to have the lenses it needs. Something that Leica are having to deal with in the SL / T Mount system. And both companies are looking to be taken seriously as some kind of 'professional mirrorless' providers. And I can't see this happening for a number of years yet, if at all.
Strangely enough Pentax got the concept right with the K-01, which while admittedly hideous design wise used the K-mount and immediately gave access to a huge range of quality lenses. And I'm really hoping that the rumoured Nikon and Canon 'pro' mirrorless systems keep the F and FE mounts, which would immediately stop them ending up with the Sony dilemma. So, if they do it right, we could end up with a lighter, smaller system that benefits from getting rid of the SLR mechanism and hopefully retains all the advantages that DSLR's still have. I would hope that Nikon and Canon would make fast operation, robust build quality and adequate battery life priorities. If they do and retain their respective mounts I would be interested. If they don't I wouldn't.
Because I'm happy with my DSLR's, as of course are many other photographers. Heavy - yes, bulky - yes, but I'm happy to accept that for the benefits I get. Not least that my Nikon and Canon DSLR gear will hold it's value over the time I own it. And it strikes me that Sony still don't really know who the FE system is for. They cannot imagine that professional photographers will dump their Canon and Nikon gear and go to Sony can they? Sure some may make the switch, but most won't. And they seem determined to charge top of the range professional spec. prices for their cameras and lenses, thus making their products out of the financial reach of the hobbyist / enthusiast market. This seems to be reflected in sales. The latest figures I've seen show that Sony aren't even the leading mirrorless manufacturer in Japan, which is touted as the place mirrorless sells well. Olympus are top in that market. So if they can't even outsell everybody else in that marketplace how on earth are they going to succeed everywhere else? And I have to say a lot of what comes out of the Sony publicity machine sounds an awful lot like Samsung were peddling a while ago and we all know what happened to them. Quite frankly, I wouldn't be at all surprised if Sony quit camera production in a year or two. They are a multi-national electronics giant after all and have a lot more options to make money.
So will DSLR's keep their current market share? Well probably not, but I can't see them not being around, because at their current state of development they are superb. The Canon 5Ds is probably the best stills cameras ever made, with it's combination of a 50MP sensor, fast operation, portability (as compared to MF) and extensive lens range, accessories, support and backup. (It's pretty good at HD video as well) Plus for speed and low light light performance the 1DX II will take some beating. Though Nikon with the newly announced D5 and D500 as well as the D810 and D750 provide pretty compelling alternatives. And for me Sony FE just isn't at this level. The only average build quality, poor battery life and poor lens choices still put me off the system and the newly announced lenses don't help. Apart from anything else the FE lenses are seriously expensive and I get much better value from Nikon and Canon, as well as more choice. And I have no use for a 24-70mm f/2.8 (not wide enough, not long enough and not fast enough) and a ridiculously heavy and expensive 70-200mm f/2.8. I still remember trying to cope with a Nikon 70-200mm f/2.8 (which is actually 10g lighter than the Sony) and I have no intention of carrying something like that around again.
Again, where are the superfast primes? Where are the light f/1.8 primes? Where are the 'long toms?' Where are the medium telephoto affordable primes? Nikon for example have a series of light, relatively inexpensive FF f/1.8 lenses. 20mm, 24mm, 28mm, 35mm, 50mm and 85mm. And it's these and their Canon equivalents that I used shooting weddings, not some slow f/2.8 brute, which are overated lenses and not that useful in low light anyway.(Plus I don't know a single professional photographer who uses one.) These light Nikon primes however are true 'workhorse' quality lenses that are very affordable and Sony will probably never make. Instead they make expensive 'headline grabbers' which apart from a few exceptions are pretty disappointing. Not a situation that would make a professional photographer switch from their Canon and Nikon DSLR's. And to be honest I used Sony FE for a while, hoping that the lenses I wanted would appear, but they won't and even though I make a decent living and buy and use a LOT and gear, I'm still shocked by Sony prices, particularly in the light of their resale value, something that Nikon and Canon lenses are good at.
And in the end Sony is an unknown quantity. I've already expressed doubts about their inclination to stick around if the going gets tough, and the piecemeal nature of the development of the FE range shows no coherent thinking, planning or commitment to a truly reliable robust system with a long term future. Sony are great at the tech. of that there is no doubt, but providing professional photographers with what they expect? I'm not convinced.
Finally, if you are tempted by the 85mm f/1.4, here's a much cheaper MF alternative, the Samsung 85mm f/1.4.