fully believing what you just said, can i just say i loved loved loved the results i saw from your time with the Df? frankly, for the first time in 30 yrs of photography your results had me seriously contemplating spending what i consider an obscene amount of money on this hobby. i still look at that super high iso shot of the blanket and yearn...and then i think there must be something to it.
Yeah, I get that. And I GOT that big time. But that shot actually IS where it's largely about f-stops. That was done at ISO 12,800 and I was looking for something to test ISO 12,800 and that was in a very very dark hallway where it needed every bit of it. I could have just as easily turned the light on!
But when I had the RX1 last summer in Italy and it was my go-to low light camera, I shot a few shots that required 10,000 or 12,800, but very VERY few. Most I could shoot comfortably at ISO 3200 or 6400. With the Fuji with the 23mm lens, I'd have been able to shoot those at one stop lower ISO because of the one stop faster lens and the results wouldn't have been much different. The Fuji is about as good at 6400 as the RX1 is at 10-12K and not far behind the Nikon at the same high ISO. No, the Fuji doesn't resolve at 24mp but neither does the DF. But in low light, it really
is about f stops vs ISO capability. For the intangible things your talking about like richness and depth, it's not. But to me full frame isn't enough better in those areas to really worry about. I took some shots in San Francisco with the XT1 using the Velvia jpeg setting that I like every bit as much as some of the best I did with the RX1. And have done in the past with other Fujis as well. When I look really closely, there's definitely a difference in detail, but there's an even bigger difference in detail with the Sigma DP series. Many of my favorite shots from Italy last summer were done with the XE1 and the 14mm lens...
I'm not denying that there's a difference. It's just a matter of how much it matters to a given shooter. To ME, the appeal of full frame IS in extending the high ISO capability and extending what's possible in low light. But for that I would have to carry the faster lenses. Maybe Nikon doesn't offer the best set of options, but if I'd gone Canon, so far they aren't using the great high ISO sensors that Nikon is. My niece is a wedding shooter who uses Canon and wishes she could switch to Nikon for the better low light capability but can't afford it. Tradeoffs, tradeoffs, tradeoffs.
And, finally, with those Nikon D or AIS lenses that I'd be comfortable with based on size and weight, most of them aren't as good as the Fuji lenses. The RX1 lens was for sure, in spades! But of the "D" lenses, I'd say the 28mm is definitely better than the Fuji 18, but the Nikon 20 doesn't compare to the Fuji 14, the Nikon 35 didn't compare to the Fuji 23, the 50's probably compared well enough with the Fuji 35, but that's not something I use so I can't say for sure. And the Nikon 85 f1.8 wasn't as nice as the Fuji 56. The Nikon 24 had no Fuji counterpart, unfortunately - Fuji still has one more fast wide angle prime on their roadmap and I'm hoping it's something in that 24-28mm range with great optics and a clutch MF ring like on the 23 and 14. I compared the Nikon 35 to the RX1 when I was trying to make up my mind on that stuff and it was good enough for me when stopped down, although not as sharp as the RX1. But anywhere close to wide open the RX1 was still excellent, the Fuji glass is still excellent (18mm excepted), but the Nikon D glass wasn't. I'd imagine the higher end Nikon glass would have been, but for reasons already mentioned, I wasn't gonna go there.
So, there is no right answer for everyone. But I've been all the way around the block now - over the last year I really scratched the full frame itch and I was seduced by it. But at the end of the day after I experienced and internalized all of the tradeoffs, I just found that for me, APS represented a better set of tradeoffs, with m43 at the longer end and with zooms. So, selfishly perhaps, I hope Fuji keeps putting at least as much energy as they have been into their APS lineup, whether they go full frame or not...
-Ray