My opinion…autofocus started the decline of the single lens reflex. Before the Minolta Maxxum hit the scene, one of the key things that separated the great cameras (Nikon F3HP, Olympus OM-*) was a clear and bright viewfinder with focus aids (Diagonal split prism with a micro prism ring around it were my favorite, and please also insert grid lines!) because that was…just…how you focused the camera. Fast forward to my last DSLR, the excellent Canon 5DS…by comparison to my ancient OM1, the viewfinder just sucks. Without autofocus or, at least focus detect lights in the viewfinder, it’s not nearly as functional or usable, particularly in anything less than full daylight. . As autofocus got better and better, and it can be pretty good these days, the need for that crisp mirror slappin‘ prism finder image was reduced, and that expensive-to-make-great component fell victim to cost cutting redesigns.
However, I will stand by the statement that autofocus has cost me as many images as it has improved, either sensor grabbing wrong focus point (which is hard to detect due to aforementioned crappy viewfinder) or just racking in and out rather than capturing the “Decisive moment”. The latter is more a problem with the craptacular autofocus capabilities of the Phase One XF, which has improved over the generations of Mamiya based AF medium format cameras from being terrible to just very bad. Ain’t progress grand?
i resisted Mirrorless, dismissing it as the typical photo equipment industry hype of “This new thing will solve all your problems, so you must now buy into a whole new platform and new lenses to get the new hotness. How else will we make our numbers this quarter?” but kind of got tricked into a mirrorless approach with the Hasselblad CFV50ii, which is as mirrorless as can be, no EV at all, just the touchscreen on the back. Compared to a Medium Format DSLR (Phase One XF) it was a true epiphany! It’s small, smaller than a 35mm full frame. It’s small and light enough to encourage use as a travel camera. Focus peaking and focus zooming with AF turned OFF to me is the best thing since Fuji made those single use Polaroid holder compatible packs for Velvia 4x5.
i encourage anyone thinking of making a leap to a different platform to reduce the risk of disappointment and photo industry overhype by arranging for some way to demo the new kit. I use lensrentals.com for that but you might also purchase from a reseller with a liberal return policy to protect yourself in case it ain’t for you. I tried the Canon mirrorless, but,despite the crap viewfinder I prefer the older, long paid for 5DS and its glass to the mirrorless version I tried. The Hasselblad however, honestly, I liked sooo much that when the 100MP version came on line, I was one of those (virtually) standing in front of the store yelling “Please take my money!!!”…the only “Brand new” kit I have purchased since my OM-4 in 1985!
All that is to say, opinions on the internet, particularly those from the massively over marketed photo industry, have almost no value compared to just getting one in your hands and spending a couple days with it.