I carried out a very interesting test today, that surprised me and I suspect will surprise you too. I've been very impressed by the 16-55mm f/2.8 Fuji zoom and I thought I'd give it a tough comparison test, up against the Sony Zeiss 35mm f/2.8 lens on the full-frame A7 Mk II.
Above are just two comparisons from a whole series of test I shot. To take account of the extra pixels of the Sony I upsized the Fuji OOC jpgs. to the same size. 6000 x 4000 pixels. Completely contrary to my expectations, the Fuji / Zoom combination turned in a better looking file than the Sony at f/2.8 and ISO 200, even after the upsizing and the Sony A7 Mk II / prime combination turned in a slightly better performance than the Fuji at f/2.8 and ISO 3200. ?????
I'm sure like me that you would have expected the opposite. Now I was skeptical of my results and did the test again, just to make sure. Same result. It was also similar at other apertures.
Now I write often about how the differences between camera are seriously exaggerated and this just proves it again. So some of the assumptions that we make are not necessarily the case. Primes are better than zooms is one of them, well not in this case.
The major surprise for me is that the Fuji jpgs. were so good. However, part of the 'problem' with the X-Trans sensor is the rendition of small-scale detail in the distance, so these close up shots won't exhibit that. Even so, I think it's a really interesting result and goes some way to demonstrating that the differences between camera / lens combinations and even different sized sensors are nowhere near as significant as people make out. Of course shooting raw and different processing would make some difference, but then if I 'developed' both in Iridient Developer and got the best out of the Fuji then I doubt there would be much difference there either.
Interesting also, that follows a couple of days when, just to see what they were like, I've been upsizing my Leica T files to 36MP. No, they are not as sharp as the files from my Sony A7r, but viewed on their own, they are perfectly capable of being significantly enlarged. This was something I was aware of some years ago when several of my 4MP Olympus E-10 files were printed A4 and looked great.
The fact is that we have had cameras that give us excellent printed images at A4 and A3 ever since we hit 12MP. Everything else that's followed that is really icing on the cake. handy for cropping certainly and should any of us want a print as large as a block of flats, then I guess we have the means to do it. But reading stuff on the photographic internet, you'd be forgiven for thinking that relatively minor increases in MP count or sensor size or lens resolution would make more difference than they actually do. Some of us work with those small margins and our commercial success (or otherwise) can often depend on the perception (rather than the reality) that size actually matters more than it does. And certainly the belief that a Zeiss badged prime in front of a 'Full Frame' sensor would perform better than a zoom in front of an APS-C sized sensor would be quite commonplace.
We do of course have to consider the fact that the A7 Mk II seems to have a pretty strong AA filter in place. But then so do the majority of Professional grade DSLR's. The Nikon 810 and the upcoming Canon offer AA free options, but then those cunning camera manufacturers go and do the same thing with software anyway. As I often write, one of the most important ways of influencing image quality is careful processing anyway. And despite my occasional flirtations with OOC jpgs. (mainly because of time constraints) I still believe that shooting raw and working out the best way to process those files for every camera / sensor / lens combination is the way to go. And we are literally spoiled for choice these days. There are a LOT of cameras and lenses that can deliver top quality results available these days and the probability is that our decisions as to what camera and / or lens to buy depends on many factors these days, because we can almost take good image quality as read.
Now whether I'd have got such a close result shooting lots of green foliage outdoors with the Fuji, who knows, I may well try it some time, but for all practical purposes and for most photographic situations, the decision as to which of these combinations to buy is very much 'You pays your money etc.....' Depending on where you shop, the prices for these two camera combinations are pretty close these days anyway, so it's not a case of saving any money. So it really is a case of pick whichever suits you best. I have to say though that for me that Fuji 16-55mm zoom looks better and better the longer I have it. But then that's just my preference. Yours is probably somewhat different.